UNITED STATES
SECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549

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FORM 10-Q

|(Mark One)                                    |  |                                                                                         
|--------------------------------------------- |  | ----------------------------------------------------------------------------------------
|ý                                             |  | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 
|For the quarterly period ended March 31, 2006
|or                                           
|o                                             |  | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from  to

Commission file number 0-14680

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GENZYME CORPORATION(Exact name of registrant as specified in its charter)

|Massachusetts                                                  |  | 06-1047163                          
|-------------------------------------------------------------- |  | ------------------------------------
|(State or other jurisdiction of
incorporation or organization) |  | (I.R.S. Employer
Identification No.)
|500 Kendall Street, Cambridge, Massachusetts                   |  | 02142                               
|(Address of principal executive offices)                       |  | (Zip Code)                          

(617) 252-7500(Registrant's telephone number, including area code)

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Indicate
by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the
preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past
90 days. Yes ý    No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of
"accelerated filer and large accelerated filer" in Rule 12b-2 of the Exchange Act. (Check one):

Large
accelerated filer ý                    Accelerated
filer o                    Non-accelerated filer o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange
Act). Yes o    No ý

The number of shares of Genzyme Stock outstanding as of April 28, 2006: 260,344,287



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NOTE REGARDING REFERENCES TO OUR COMMON STOCK

Throughout this Form 10-Q, the words "we," "us," "our" and "Genzyme" refer to Genzyme Corporation as a whole, and "our board of directors"
refers to the board of directors of Genzyme Corporation. Genzyme Corporation has one outstanding series of common stock, which we refer to as "Genzyme Stock."

NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Form 10-Q contains forward-looking statements, including statements regarding:



2

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These
statements are subject to risks and uncertainties, and our actual results may differ materially from those that are described in this report. These risks and uncertainties include:



3

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We
have included more detailed descriptions of these and other risks and uncertainties in Item 2 of this report under the heading "Factors Affecting Future Operating Results." We
encourage you to read those descriptions carefully. We caution investors not to place substantial reliance on the forward-looking statements contained in this report. These statements, like all
statements in this report, speak only as of the date of this report (unless another date is indicated) and we undertake no obligation to update or revise the statements.

NOTE REGARDING INCORPORATION BY REFERENCE

The Securities and Exchange Commission, commonly referred to as the SEC, allows us to disclose important information to you by referring you to other documents we
have filed with the SEC. The information that we refer you to is "incorporated by reference" into this Form 10-Q. Please read that information.

NOTE REGARDING TRADEMARKS

Genzyme®, Cerezyme®, Fabrazyme®, Thyrogen®, Aldurazyme®, Myozyme®, Renagel®,
Thymoglobulin®, Campath®, Clolar®, Synvisc®, Carticel®, Seprafilm®, IMPATH®, MACI®,
GlucaMesh®, GlucaTex® and Hectorol® are registered trademarks, and Lymphoglobuline and Sepra are trademarks, of Genzyme or its
subsidiaries. WelChol® is a registered trademark of Sankyo Pharma, Inc. All rights reserved.

4

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GENZYME CORPORATION AND SUBSIDIARIES  FORM 10-Q, MARCH 31, 2006  TABLE OF CONTENTS

|           |  |                                                                                                                              |  | PAGE NO.
|---------- |  | ---------------------------------------------------------------------------------------------------------------------------- |  | --------
|PART I.    |  | FINANCIAL INFORMATION                                                                                                        |  | 6       
|ITEM 1.    |  | Financial Statements                                                                                                         |  | 6       
|           |  | Unaudited, Consolidated Statements of Operations and Comprehensive Income for the Three Months Ended March 31, 2006 and 2005 |  | 6       
|           |  | Unaudited, Consolidated Balance Sheets as of March 31, 2006 and December 31, 2005                                            |  | 7       
|           |  | Unaudited, Consolidated Statements of Cash Flows for the Three Months Ended March 31, 2006 and 2005                          |  | 8       
|           |  | Notes to Unaudited, Consolidated Financial Statements                                                                        |  | 9       
|ITEM 2.    |  | Management's Discussion and Analysis of Financial Condition and Results of Operations                                        |  | 32      
|ITEM 3.    |  | Quantitative and Qualitative Disclosures About Market Risk                                                                   |  | 64      
|ITEM 4.    |  | Controls and Procedures                                                                                                      |  | 66      
|PART II.   |  | OTHER INFORMATION                                                                                                            |  | 67      
|ITEM 1.    |  | Legal Proceedings                                                                                                            |  | 67      
|ITEM 1A.   |  | Risk Factors                                                                                                                 |  | 68      
|ITEM 2.    |  | Unregistered Sales of Equity Securities and Use of Proceeds                                                                  |  | 68      
|ITEM 6.    |  | Exhibits                                                                                                                     |  | 68      
|Signatures |  | 69                                                                                                                          

5

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PART I. FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

GENZYME CORPORATION AND SUBSIDIARIES        Consolidated Statements of Operations and Comprehensive Income        (Unaudited, amounts in thousands, except per share amounts)

|                                     |                                                      | Three Months Ended
March 31,             |                                                                                         
|------------------------------------ | ---------------------------------------------------- | ---------------------------------------- | ----------------------------------------------------------------------------------------
|
|Revenues:                            |                                                      |                                          |                                                                                         
|                                     | Net product sales                                    |                                          | $                                                                                       
|                                     | Net service sales                                    |                                          |                                                                                         
|                                     | Research and development revenue                     |                                          |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      |                                          | Total revenues                                                                          
|                                     |                                                      |                                          |                                                                                         
|Operating costs and expenses:        |                                                      |                                          |                                                                                         
|                                     | Cost of products sold                                |                                          |                                                                                         
|                                     | Cost of services sold                                |                                          |                                                                                         
|                                     | Selling, general and administrative                  |                                          |                                                                                         
|                                     | Research and development                             |                                          |                                                                                         
|                                     | Amortization of intangibles                          |                                          |                                                                                         
|                                     | Purchase of in-process research and development      |                                          |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      |                                          | Total operating costs and expenses                                                      
|                                     |                                                      |                                          |                                                                                         
|Operating income                     |                                                      |                                          | 128,208                                                                                 
|                                     |                                                      |                                          |                                                                                         
|Other income (expenses):             |                                                      |                                          |                                                                                         
|                                     | Equity in income (loss) of equity method investments |                                          |                                                                                         
|                                     | Minority interest                                    |                                          |                                                                                         
|                                     | Gains on investments in equity securities            |                                          |                                                                                         
|                                     | Other                                                |                                          |                                                                                         
|                                     | Investment income                                    |                                          |                                                                                         
|                                     | Interest expense                                     |                                          |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      |                                          | Total other income                                                                      
|                                     |                                                      |                                          |                                                                                         
|Income before income taxes           |                                                      |                                          | 146,343                                                                                 
|Provision for income taxes           |                                                      |                                          | (45,369                                                                                 
|                                     |                                                      |                                          |                                                                                         
|Net income                           |                                                      | $                                        | 100,974                                                                                 
|                                     |                                                      |                                          |                                                                                         
|Net income per share:                |                                                      |                                          |                                                                                         
|                                     | Basic                                                |                                          | $                                                                                       
|                                     |                                                      |                                          |                                                                                         
|                                     | Diluted                                              |                                          | $                                                                                       
|                                     |                                                      |                                          |                                                                                         
|Weighted average shares outstanding: |                                                      |                                          |                                                                                         
|                                     | Basic                                                |                                          |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     | Diluted                                              |                                          |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|Comprehensive income, net of tax:    |                                                      |                                          |                                                                                         
|                                     | Net income                                           |                                          | $                                                                                       
|                                     |                                                      |                                          |                                                                                         
|                                     | Other comprehensive income (loss):                   |                                          |                                                                                         
|                                     |                                                      | Foreign currency translation adjustments |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      | Other, net of tax                        |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      | Unrealized gains (losses) on securities: |                                                                                         
|                                     |                                                      |                                          | Unrealized gains (losses) arising during the period                                     
|                                     |                                                      |                                          | Reclassification adjustment for (gains) losses included in net income (loss), net of tax
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      |                                          | Unrealized gains (losses) on securities, net                                            
|                                     |                                                      |                                          |                                                                                         
|                                     |                                                      | Other comprehensive income (loss)        |                                                                                         
|                                     |                                                      |                                          |                                                                                         
|Comprehensive income                 |                                                      | $                                        | 132,323                                                                                 
|                                     |                                                      |                                          |                                                                                         

The accompanying notes are an integral part of these unaudited, consolidated financial statements.

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GENZYME CORPORATION AND SUBSIDIARIES        Consolidated Balance Sheets        (Unaudited, amounts in thousands, except par value amounts)

|                                                          |                                                                 | March 31,
2006                             |           | December 31,
2005 |          
|--------------------------------------------------------- | --------------------------------------------------------------- | ------------------------------------------ | --------- | ----------------- | ---------
|ASSETS                                                    |                                                                 |                                            |           |                   |          
|Current assets:                                           |                                                                 |                                            |           |                   |          
|                                                          | Cash and cash equivalents                                       |                                            | $         | 352,587           |          
|                                                          | Short-term investments                                          |                                            |           | 227,857           |          
|                                                          | Accounts receivable, net                                        |                                            |           | 629,968           |          
|                                                          | Inventories                                                     |                                            |           | 316,427           |          
|                                                          | Prepaid expenses and other current assets                       |                                            |           | 93,824            |          
|                                                          | Notes receivablerelated parties                                |                                            |           |                  |          
|                                                          | Deferred tax assets                                             |                                            |           | 172,173           |          
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total current assets                       |           |                   | 1,792,836
|Property, plant and equipment, net                        |                                                                 |                                            | 1,370,274 |                   |          
|Long-term investments                                     |                                                                 |                                            | 620,639   |                   |          
|Notes receivablerelated parties                          |                                                                 |                                            | 7,218     |                   |          
|Goodwill                                                  |                                                                 |                                            | 1,487,569 |                   |          
|Other intangible assets, net                              |                                                                 |                                            | 1,558,111 |                   |          
|Investments in equity securities                          |                                                                 |                                            | 130,317   |                   |          
|Other noncurrent assets                                   |                                                                 |                                            | 60,962    |                   |          
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total assets                               |           | $                 | 7,027,926
|                                                          |                                                                 |                                            |           |                   |          
|LIABILITIES AND STOCKHOLDERS' EQUITY                      |                                                                 |                                            |           |                   |          
|Current liabilities:                                      |                                                                 |                                            |           |                   |          
|                                                          | Accounts payable                                                |                                            | $         | 72,759            |          
|                                                          | Accrued expenses                                                |                                            |           | 376,857           |          
|                                                          | Income taxes payable                                            |                                            |           | 42,987            |          
|                                                          | Deferred revenue and other income                               |                                            |           | 17,263            |          
|                                                          | Current portion of long-term debt and capital lease obligations |                                            |           | 6,029             |          
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total current liabilities                  |           |                   | 515,895  
|Long-term debt and capital lease obligations              |                                                                 |                                            | 124,547   |                   |          
|Convertible notes                                         |                                                                 |                                            | 690,000   |                   |          
|Deferred revenuenoncurrent                               |                                                                 |                                            | 4,707     |                   |          
|Deferred tax liabilities                                  |                                                                 |                                            | 316,362   |                   |          
|Other noncurrent liabilities                              |                                                                 |                                            | 23,906    |                   |          
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total liabilities                          |           |                   | 1,675,417
|                                                          |                                                                 |                                            |           |                   |          
|Commitments and contingencies (See Notes 5, 7, 10 and 11) |                                                                 |                                            |           |                   |          
|Stockholders' equity:                                     |                                                                 |                                            |           |                   |          
|                                                          | Preferred stock, $0.01 par value                                |                                            |           |                  |          
|                                                          | Common stock, $0.01 par value                                   |                                            |           | 2,601             |          
|                                                          | Additional paid-in capital                                      |                                            |           | 4,758,237         |          
|                                                          | Notes receivable from stockholders                              |                                            |           | (14,596           | )        
|                                                          | Accumulated earnings                                            |                                            |           | 430,430           |          
|                                                          | Accumulated other comprehensive income                          |                                            |           | 175,837           |          
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total stockholders' equity                 |           |                   | 5,352,509
|                                                          |                                                                 |                                            |           |                   |          
|                                                          |                                                                 | Total liabilities and stockholders' equity |           | $                 | 7,027,926
|                                                          |                                                                 |                                            |           |                   |          

The accompanying notes are an integral part of these unaudited, consolidated financial statements.

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GENZYME CORPORATION AND SUBSIDIARIES        Consolidated Statements of Cash Flows        (Unaudited, amounts in thousands)

|                                                 |                                                                       | Three Months Ended
March 31,                                                                                            |                                                        
|------------------------------------------------ | --------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------
|
|Cash Flows from Operating Activities:            |                                                                       |                                                                                                                         |                                                        
|                                                 | Net income                                                            |                                                                                                                         | $                                                      
|                                                 | Reconciliation of net income to cash flows from operating activities: |                                                                                                                         |                                                        
|                                                 |                                                                       | Depreciation and amortization                                                                                           |                                                        
|                                                 |                                                                       | Stock-based compensation                                                                                                |                                                        
|                                                 |                                                                       | Provision for bad debts                                                                                                 |                                                        
|                                                 |                                                                       | Purchase of in-process research and development                                                                         |                                                        
|                                                 |                                                                       | Minority interest                                                                                                       |                                                        
|                                                 |                                                                       | Equity in (income) loss of equity method investments                                                                    |                                                        
|                                                 |                                                                       | Gain on sale of investments in equity securities                                                                        |                                                        
|                                                 |                                                                       | Deferred income tax benefit                                                                                             |                                                        
|                                                 |                                                                       | Tax benefit from employee stock compensation                                                                            |                                                        
|                                                 |                                                                       | Excess tax benefits from stock-based compensation                                                                       |                                                        
|                                                 |                                                                       | Other                                                                                                                   |                                                        
|                                                 |                                                                       | Increase (decrease) in cash from working capital changes (excluding impact of acquired assets and assumed liabilities): |                                                        
|                                                 |                                                                       |                                                                                                                         | Accounts receivable                                    
|                                                 |                                                                       |                                                                                                                         | Inventories                                            
|                                                 |                                                                       |                                                                                                                         | Prepaid expenses and other current assets              
|                                                 |                                                                       |                                                                                                                         | Income taxes payable                                   
|                                                 |                                                                       |                                                                                                                         | Accounts payable, accrued expenses and deferred revenue
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|Cash Flows from Investing Activities:            |                                                                       |                                                                                                                         |                                                        
|                                                 | Purchases of investments                                              |                                                                                                                         |                                                        
|                                                 | Sales and maturities of investments                                   |                                                                                                                         |                                                        
|                                                 | Purchases of equity securities                                        |                                                                                                                         |                                                        
|                                                 | Proceeds from sales of investments in equity securities               |                                                                                                                         |                                                        
|                                                 | Purchases of property, plant and equipment                            |                                                                                                                         |                                                        
|                                                 | Distributions from equity method investees                            |                                                                                                                         |                                                        
|                                                 | Purchases of intangible assets                                        |                                                                                                                         |                                                        
|                                                 | Acquisitions, net of acquired cash                                    |                                                                                                                         |                                                        
|                                                 | Acquisition of sales and marketing rights                             |                                                                                                                         |                                                        
|                                                 | Other                                                                 |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|Cash Flows from Financing Activities:            |                                                                       |                                                                                                                         |                                                        
|                                                 | Proceeds from issuance of common stock                                |                                                                                                                         |                                                        
|                                                 | Excess tax benefits from stock-based compensation                     |                                                                                                                         |                                                        
|                                                 | Payments of debt and capital lease obligations                        |                                                                                                                         |                                                        
|                                                 | Bank overdraft                                                        |                                                                                                                         |                                                        
|                                                 | Minority interest contributions                                       |                                                                                                                         |                                                        
|                                                 | Other                                                                 |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|                                                 |                                                                       |                                                                                                                         |                                                        
|Effect of exchange rate changes on cash          |                                                                       |                                                                                                                         | 1,099                                                  
|                                                 |                                                                       |                                                                                                                         |                                                        
|Increase (decrease) in cash and cash equivalents |                                                                       |                                                                                                                         | 60,627                                                 
|Cash and cash equivalents at beginning of period |                                                                       |                                                                                                                         | 291,960                                                
|                                                 |                                                                       |                                                                                                                         |                                                        
|Cash and cash equivalents at end of period       |                                                                       | $                                                                                                                       | 352,587                                                
|                                                 |                                                                       |                                                                                                                         |                                                        

The accompanying notes are an integral part of these unaudited, consolidated financial statements

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GENZYME CORPORATION AND SUBSIDIARIES        Notes To Unaudited, Consolidated Financial Statements

1. Description of Business

We are a global biotechnology company dedicated to making a major impact on the lives of people with serious diseases. Our broad product and service portfolio is
focused on rare disorders, renal diseases, orthopaedics, organ transplant, and diagnostic and predictive testing. We are organized into five financial reporting units, which we also consider to be our
reporting segments:



We
report the activities of our oncology, bulk pharmaceuticals, including sales of WelChol, and cardiovascular business units under the caption "Other." We report our general and
administrative operations and corporate science activities under the caption "Corporate."

Effective
January 1, 2006, as a result of changes in how we review our business, certain general and administrative expenses, as well as research and development expenses related
to our preclinical development programs, which were formerly allocated amongst our reporting segments and Other, are now allocated to Corporate. We have revised our 2005 segment disclosures to conform
to our 2006 presentation.

2. Basis of Presentation and Significant Accounting Policies



Our unaudited, consolidated financial statements for each period include the statements of operations and comprehensive income, balance sheets and statements of
cash flows for our operations taken as a whole. We have eliminated all intercompany items and transactions in consolidation. We prepare our unaudited, consolidated financial statements following the
requirements of the SEC for interim reporting. As permitted under these rules, we condense or omit certain footnotes and other financial information that are normally required by accounting principles
generally accepted in the

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United
States. In addition to the revisions to our segment disclosures described above, we have reclassified certain other 2005 data to conform to our 2006 presentation.

These
financial statements include all normal and recurring adjustments that we consider necessary for the fair presentation of our financial position and operating results. Since these
are interim financial statements, you should also read our audited, consolidated financial statements and notes included in our 2005 Form 10-K. Revenues, expenses, assets and
liabilities can vary from quarter to quarter. Therefore, the results and trends in these interim financial statements may not be indicative of results for future periods.



Prior to January 1, 2006, we elected to:



Effective
January 1, 2006, we adopted the provisions of:



FAS 123R
applies to stock options granted under our employee and director stock option plans and purchases made under our ESPP, and will also apply to any restricted stock or restricted stock
units we may grant in the future.

We
adopted FAS 123R using the modified prospective transition method, which requires us to apply the standard to new equity awards and to equity awards modified, repurchased or
canceled after January 1, 2006, our adoption date. Additionally, compensation expense for the unvested portion of awards granted prior to our adoption date shall be:



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The
modified prospective transition method does not allow for the restatement of prior periods. Accordingly, our results of operations for the three months ended March 31, 2006 and future
periods will not be comparable to our results of operations prior to January 1, 2006 because our historical results prior to that date do not reflect the impact of expensing the fair value of
share-based payment awards.

Prior
to January 1, 2006, in the pro forma disclosures regarding stock-based compensation included in the notes to our financial statements, we recognized forfeitures of stock
options only as they occurred. Effective January 1, 2006, in accordance with the provisions of FAS 123R, we are now required to estimate an expected forfeiture rate for stock options,
which is factored into the determination of our monthly stock-based compensation expense. As a result of the adoption of FAS 123R, we recorded pre-tax stock-based compensation
expense totaling $32.6 million, net of estimated forfeitures, in our statement of operations for the three months ended March 31, 2006. Additional information regarding our stock-based
compensation is included in Note 3, "Stock-Based Compensation," to our financial statements included in this report.

In
connection with the adoption of FAS 123R, we were also required to change the classification, in our consolidated statements of cash flows, of any tax benefits realized upon
the exercise of stock options in excess of that which is associated with the expense recognized for financial reporting purposes. These amounts are presented as a financing cash inflow rather than as
a reduction of income taxes paid in our consolidated statement of cash flows.

Recent Accounting Pronouncements

FAS 151, "Inventory Costs, an amendment of ARB No. 43, Chapter 4."In November 2004, the FASB issued
FAS 151, "Inventory Costs, an amendment of ARB No. 43, Chapter 4," which clarifies that abnormal amounts of idle facility expense, freight, handling costs and wasted material (spoilage)
should be recognized as current period charges in all circumstances. Our adoption of FAS 151, effective January 1, 2006, did not have a material impact on our financial position or
results of operations.

FAS 154, "Accounting Changes and Error Corrections, a replacement of APB Opinion No. 20 and FASB Statement No. 3."In
May 2005, the FASB issued FAS 154, "Accounting Changes and Error Corrections, a replacement of APB Opinion No. 20 and FASB Statement No. 3." FAS 154 applies to all
voluntary changes in the accounting for and reporting of changes in accounting principles and requires retrospective application to prior periods' financial statements of a voluntary change in
accounting principles unless it is not practical to do so. APB Opinion No. 20, "Accounting Changes," previously required that most voluntary changes in accounting principles be recognized by
including in net income (loss), for the period of the change, the cumulative effect of changing to the new accounting principle. FAS 154 also requires that a change in depreciation,
amortization, or depletion method for
long-lived non-financial assets be accounted for as a change in accounting estimate affected by a change in accounting principle. FAS 154 is effective for accounting
changes and corrections of errors made in fiscal years beginning after December 15, 2005. Our adoption of FAS 154, effective January 1, 2006, did not impact our financial position
or results of operations.

FSP Nos. FAS 115-1 and FAS 124-1, "The Meaning of Other-Than-Temporary Impairment and Its
Application to Certain Investments."In November 2005, the FASB issued FASB Staff Position, or FSP, Nos. FAS 115-1 and FAS 124-1,
"The Meaning of Other-Than-Temporary Impairment and Its Application to Certain Investments." FSP Nos. FAS 115-1 and FAS 124-1 address the
determination as

11

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to
when an investment is considered impaired, whether that impairment is other than temporary, and the measurement of an impairment loss. The FSPs also include accounting considerations subsequent to
the recognition of an other-than-temporary impairment and requires certain disclosures about unrealized losses that have not been recognized as
other-than-temporary impairments. The guidance in the FSPs clarify FAS 115, "Accounting for Certain Investments in Debt and Equity Securities," FAS 124,
"Accounting for Certain Investments Held by Not-for-Profit Organizations," and APB Opinion No. 18, "The Equity Method of Accounting for Investments in Common Stock." We
reviewed the guidance provided in FSP Nos. FAS 115-1 and FAS 124-1 and have determined that our current practices are consistent with the guidance included in the
FSPs. As a result, our adoption of the FSPs, effective January 1, 2006, did not impact our financial position and results of operations.

FAS 155, "Accounting for Certain Hybrid Financial Instrumentsan amendment of FASB Statements No. 133 and 140."In February 2006, the FASB issued FAS 155, "Accounting for Certain Hybrid Financial Instrumentsan amendment of FASB Statements No. 133 and 140," which permits a fair
value remeasurement for any hybrid financial instrument that contains an embedded derivative that would otherwise require bifurcation. This accounting standard is effective as of the beginning of
fiscal years beginning after September 15, 2006. We have not yet determined the effect, if any, the adoption of FAS 155 may have on our financial position and results of operations.

FAS 156, "Accounting for Servicing of Financial Assetsan amendment of FASB Statement No. 140."In
March 2006, the FASB issued FAS 156, "Accounting for Servicing of Financial Assets, an amendment of FASB Statement No. 140," which requires that servicing assets and servicing
liabilities be recognized at fair value, if practicable, when we enter into a servicing agreement and allows two alternatives, the amortization and fair value measurement methods, as subsequent
measurement methods. This accounting standard is effective for all new transactions occurring as of the beginning of fiscal years beginning after September 15, 2006. We have not yet determined
the effect, if any, the adoption of FAS 156 may have on our financial position and results of operations.

3. Stock-Based Compensation

Equity Plans



The purpose of our stock option plans is to attract, retain and motivate our key employees, consultants and directors, upon whose judgment, initiative and efforts
the financial success and growth of our business largely depends. Options granted under these plans can be either incentive stock

12

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options
(ISO) or nonstatutory stock options (NSO), as specified in the individual plans. The following table contains information about our stock option plans:

|                                   |  |                                                    |  |         |  | As of March 31, 2006
|---------------------------------- |  | -------------------------------------------------- |  | ------- |  | --------------------
|
|2004 Equity Incentive Plan(1)      |  | All key employees and consultants                  |  | ISO/NSO |  | 16,643,159          
|2001 Equity Incentive Plan(1)      |  | All key employees and consultants                  |  | ISO/NSO |  | 10,708,057          
|1997 Equity Incentive Plan(1)      |  | All key employees and consultants, except officers |  | NSO     |  | 13,788,960          
|1998 Director Stock Option Plan(2) |  | Non-employee board members                         |  | NSO     |  | 686,291             
|Assumed Options(3)                 |  |                                                    |  |         |  |                    
|                                   |  |                                                    |  |         |  |                     
|                                   |  |                                                    |  |         |  | 41,826,467          
|                                   |  |                                                    |  |         |  |                     

---

Beginning in 2006, all stock-based awards to non-employees are accounted for at their fair value in accordance with FAS 123 and
Emerging Issues Task Force, or EITF, Issue No. 96-18, "Accounting for Equity Instruments that are Issued to Other than Employees for Acquiring, or in Conjunction with Selling, Goods
or Services."

We
account for options granted to our employees and directors under the fair value method of accounting using a Black-Scholes valuation model to measure stock option expense at the date
of grant. All stock option grants have an exercise price equal to the fair market value of Genzyme Stock on the date of grant and generally have a 10-year term and vest in increments,
generally over four years from the date of grant, although we may grant options with different vesting terms from time to time. Excluding our directors, when an employee at or over the age of 60 with
at least five years of service retires, the employee's options automatically become fully vested and will expire three years after the employee's retirement date or on the original expiration date at
the time the options were granted, whichever is earlier. Upon termination of employment, an employee's unexercised options will expire

13

---



three
months after the employee's termination date. We recognize stock-based compensation expense for each grant on a graded-vested basis over the employee's or director's requisite service period,
generally the vesting period of the award, which is usually four years. Additionally, stock-based compensation expense related to stock options includes an estimate for pre-vesting
forfeitures. Effective January 1, 2006, in connection with our adoption of FAS 123R, we now recognize stock-based compensation expense immediately for awards granted to retirement
eligible employees or over the period from the grant date to the date retirement eligibility is achieved, if that is expected to occur during the nominal vesting period. Grants to retirement eligible
employees prior to January 1, 2006 are not subject to accelerated vesting and continue to vest over the nominal vesting period. Shares issued as a result of stock option exercises are funded
through the issuance of new shares.

ESPP

Our 1999 ESPP allows employees to purchase our stock at a discount. Under this plan, the purchase price per share of Genzyme Stock is 85% of the lower of the fair
market value of Genzyme Stock at the beginning of an enrollment period or on the purchase date. There are 5,829,391 shares of Genzyme Stock authorized for purchase under the plan as of
March 31, 2006, of which 1,501,860 remain available. We place limitations on the number of shares of stock that can be purchased under the plan in a given year.

Adoption of FAS 123R

As
a result of adopting FAS 123R, for the three months ended March 31, 2006, we recorded pre-tax stock-based compensation expense, net of estimated forfeitures,
totaling $32.6 million, which was allocated based on the functional cost center of each employee granted options or participating in our ESPP plan as follows (amounts in thousands):

Three Months Ended
March 31, 2006Pre-tax stock-based compensation expense, net of estimated forfeitures:Cost of products and services sold

$
2,303Selling, general and administrative


19,447Research and development


10,857Total


32,607Less: tax benefit of stock options


10,348Stock-based compensation expense, net of tax

$
22,259


The
$22.3 million of stock-based compensation expense, net of estimated forfeitures and tax benefits, for the three months ended March 31, 2006 reduced our net income per share by $0.09
per basic share and $0.08 per diluted share. In addition, we capitalized $2.7 million of stock compensation to inventory, all of which is attributable to participating employees that support
our manufacturing operations. At March 31, 2006, there was $242.8 million of pre-tax compensation expense, net of estimated forfeitures, related to nonvested awards not yet recognized
which is expected to be recognized over a weighted average period of 2.2 years.

14

---





Pro Forma Information for the Period Prior to Adoption of FAS 123R

Prior to the adoption of FAS 123R, we accounted for stock options granted to employees in accordance with APB 25 and provided the disclosures
required under FAS 123 only in the notes to our financial statements. As a result, no stock-based compensation expense was reflected in our net income for the three months ended
March 31, 2005 related to our ESPP or stock options, since all options granted had an exercise price equal to the market value of the underlying common stock on the date of grant.

The
following table sets forth our historical disclosure of our pro forma net income and net income per share data for the three months ended March 31, 2005 as if compensation
expense for our stock-based compensation plans was determined in accordance with FAS 123 based on the grant date fair value of the awards (amounts in thousands):

Three Months Ended
March 31, 2005Net income:As reported

$
95,558Deduct: pro forma employee stock-based compensation expense, net of tax(1)


(19,258
)Pro forma(1)

$
76,300


|Net income per share: |          |             
|--------------------- | -------- | ------------
|                      | Basic:   |             
|                      |          | As reported 
|                      |          |             
|                      |          | Pro forma(1)
|                      |          |             
|                      | Diluted: |             
|                      |          | As reported 
|                      |          |             
|                      |          | Pro forma(1)
|                      |          |             

---

Valuation Assumptions for Stock Option Plans and ESPP

The employee stock-based compensation expense recognized under FAS 123R and presented in the pro forma disclosure required under FAS 123 was
determined using the Black-Scholes option

15

---



valuation
model. Option valuation models require the input of subjective assumptions and these assumptions can vary over time. The weighted average assumptions used are as follows:

Three Months Ended
March 31,2006

2005Risk-free interest rate

4.7
%
4.2
%Dividend yield

0
%
0
%Expected option life (in years)

5

5Volatility-stock options

45
%
52
%Volatility-ESPP

27%-28
%
52
%


The
risk-free interest rate is based on the U.S. Treasury yield curve in effect on the date of grant. The dividend yield percentage is zero because we do not currently pay dividends nor
intend to do so during the expected option life. We used historical data on exercises of our stock options and other factors to estimate the expected option life (in years), or term, of the
share-based payments granted. We determined the volatility rate for stock options based on the 5-year volatility of Genzyme Stock. We determine separate volatility rates for each
enrollment under our ESPP based on the commencement date of each enrollment. Stock option expense in future periods will be based upon the Black-Scholes values determined at the date of each grant or
the date of each purchase under our ESPP.

Stock Option Plan Activity

The
following table contains information regarding stock option plan activity for the three months ended March 31, 2006:

|                                 |  | Shares Under
Option |   | Weighted
Average
Exercise Price |       | Number
Exercisable
|-------------------------------- |  | ------------------- | - | ------------------------------- | ----- | ------------------
|Outstanding at December 31, 2005 |  | 32,345,317          |   | $                               | 47.71 |                   
|Granted                          |  | 236,350             |   |                                 | 69.66 |                   
|Exercised                        |  | (592,457            | ) |                                 | 36.47 |                   
|Forfeited and cancelled          |  | (244,068            | ) |                                 | 65.26 |                   
|                                 |  |                     |   |                                 |       |                   
|Outstanding at March 31, 2006    |  | 31,745,142          |   | $                               | 47.96 |                   
|                                 |  |                     |   |                                 |       |                   

The
following table contains information regarding the pre-tax intrinsic value of our stock options, the estimated fair value of shares vested and the weighted average grant date fair
value per share of

16

---



stock
options granted under our stock plans during the three months ended March 31, 2006 and 2005 (amounts in thousands, except per share amounts):

Three Months Ended March 31,2006

2005Pre-tax intrinsic value of options exercised

$
20,645

$
66,558Estimated fair value of shares vested

$
16,662

$
11,105Weighted average grant date fair value per share of stock options granted under our stock plans

$
31.49

$
28.59


For
the three months ended March 31, 2006, we:



The
following table contains information regarding the range of stock option prices as of March 31, 2006:

|                  |  |            |  | Weighted
Average
Remaining
Contractual
Life |  |   |        | Exercisable
|----------------- |  | ---------- |  | ------------------------------------------- |  | - | ------ | -----------
|
|$1.75  $26.50    |  | 2,972,166  |  | 3.16                                        |  | $ | 20.82  |            
|26.79  43.78     |  | 5,347,922  |  | 5.39                                        |  |   | 32.53  |            
|43.80  46.24     |  | 10,466,240 |  | 7.66                                        |  |   | 45.01  |            
|46.25  53.47     |  | 4,189,009  |  | 5.47                                        |  |   | 52.26  |            
|53.57  70.89     |  | 8,104,150  |  | 8.95                                        |  |   | 62.53  |            
|71.07  2,356.12  |  | 665,655    |  | 6.45                                        |  |   | 134.66 |            
|                  |  |            |  |                                             |  |   |        |            
|$1.75  $2,356.12 |  | 31,745,142 |  | 6.87                                        |  | $ | 47.96  |            
|                  |  |            |  |                                             |  |   |        |            

As
of March 31, 2006, the aggregate intrinsic value of all outstanding stock options was $657.0 million and the aggregate intrinsic value of the exercisable
options was $443.9 million.

ESPP Activity

The following table shows our ESPP activity for the three months ended March 31, 2006:

Shares Issued

Shares Under
ESPPAvailable for purchase as of December 31, 2005

1,712,481Shares purchased by employees

(210,621
)Available for purchase as of March 31, 2006

1,501,860


17

---



4. Net Income Per Share

The following table sets forth our computation of basic and diluted net income per share (amounts in thousands, except per share amounts):

Three Months Ended
March 31,2006

2005Net incomebasic(1)

$
100,974

$
95,558Effect of dilutive securities:Interest expense and debt fees, net of tax, related to our 1.25% convertible senior notes


1,874


1,874Net incomediluted(1)

$
102,848

$
97,432Shares used in computing net income per common
sharebasic


259,709


250,921Effect of dilutive securities:Shares issuable for the assumed conversion of our 1.25% convertible senior notes


9,686


9,686Stock options(1,2)


7,403


7,276Warrants and stock purchase rights


11


10Dilutive potential common shares


17,100


16,972Shares used in computing net income per common sharediluted(1,2)


276,809


267,893Net income per share(1):Basic

$
0.39

$
0.38Diluted

$
0.37

$
0.36


---

Three Months Ended
March 31,2006

2005Shares of Genzyme Stock issuable upon exercise of outstanding options

7,863

8,325


18

---



5. Mergers and Acquisitions

Acquisition of Surgi.B SAS

In March 2006, we acquired Surgi.B Chirugie et Medicine SAS, or Surgi.B, a privately-held company based in Beauzelle, France, which owned the exclusive
rights to manufacture and sell GlucaMesh and GlucaTex, two beta glucan-coated mesh products for use in the surgical repair of inguinal hernias, for an up-front cash payment of $5.5 million. In
addition, we are obligated to make certain milestone payments totaling up to approximately $6 million and royalty payments based on future sales of GlucaMesh and GlucaTex.

Acquisition of Gene Therapy Assets from Avigen, Inc.

In December 2005, we acquired certain gene therapy assets from Avigen, Inc., or Avigen, a publicly-traded, biopharmaceutical company based in Alameda,
California with a focus on unique small molecule therapeutics and biologics to treat serious neurological disorders, in exchange for an up-front cash payment of $12.0 million. In
addition, we may be obligated to make up to approximately $38 million of potential milestone payments based on the development and approval of, and royalty payments based on the sale of,
products developed between now and 2020 that rely on the intellectual property purchased from Avigen.

In-Process Research and Development

In connection with our acquisition of certain gene therapy assets from Avigen, we acquired IPR&D related to Avigen's Parkinson's disease program.

As
of the date this transaction closed, this program had not reached technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D and charged to
expense in our consolidated statements of operations in December 2005, $7.0 million, representing the portion of the $12.0 million up-front payment to Avigen
attributable to the Parkinson's disease program.

As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $74 million to complete the development of, obtain approval
for and commercialize a product arising from the acquired Parkinson's disease program.

Acquisition of Bone Care

In July 2005, we acquired Bone Care, a publicly-held specialty pharmaceutical company based in Middleton, Wisconsin with a focus on nephrology.
We paid gross consideration of $712.3 million in cash. We accounted for the acquisition as a purchase and accordingly, included its results of operations in our consolidated statements of
operations from July 1, 2005, the date of acquisition.

In
October 2004, Bone Care was one of seven companies, all of which market treatments, therapies or diagnostics for kidney patients, which received a subpoena from the office of
the United States Attorney for the Eastern District of New York. The subpoena required Bone Care to provide a wide range of documents related to numerous aspects of its business and operations. The
subpoena included specific requests for documents related to testing for parathyroid hormone levels and vitamin D therapies. Bone Care has cooperated, and we continue to cooperate, with the
government's investigation. To our knowledge, no civil or criminal proceedings have been initiated against Bone Care or Genzyme at this time, although we cannot predict when or if any proceedings
might be initiated. As a result, we have not recorded any contingent liabilities related to this investigation. Any such liabilities

19

---



that
may arise out of this investigation will be recorded in our consolidated financial statements, if they become probable and estimable prior to July 2006, as an increase to both the goodwill
resulting from, and the liabilities assumed in connection with, our acquisition of Bone Care.

The
allocation of the purchase price remains subject to potential adjustments, including adjustments for liabilities associated with certain exit activities, tax restructuring activities
and liabilities that may arise from the government's investigation of Bone Care. Pro forma results are not presented for the acquisition of Bone Care because the acquisition did not have a material
effect on our results of operations.

In-Process Research and Development

In connection with our acquisition of Bone Care, we acquired IPR&D related to LR-103, a vitamin D therapeutic candidate that is an active metabolite
of Hectorol.

As
of the date this transaction closed, this program had not reached technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D and charged to
expense in our consolidated statements of operations in September 2005, $12.7 million, representing the portion of the purchase price attributable to this program.

As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $15 million to complete the development of, obtain approval
for and commercialize LR-103.

Exit Activities

In connection with our acquisition of Bone Care, we initiated an integration plan to consolidate and restructure certain functions and operations, including the
relocation and termination of certain Bone Care personnel. These costs have been recognized as liabilities assumed in connection with the acquisition of Bone Care in accordance with EITF Issue
No. 95-3, "Recognition of Liabilities in Connection with a Purchase Business Combination," and are subject to potential adjustments as certain exit activities are confirmed or
refined. The following table summarizes the liabilities established for exit activities related to the acquisition of Bone Care (amounts in thousands):

Employee
Related
Benefits

Other
Exit
Activities

Total
Exit
ActivitiesRecorded at acquisition date

$
10,759

$
382

$
11,141Revision of estimate


80





80Payments in 2005


(9,099
)




(9,099
)Balance at December 31, 2005


1,740


382


2,122Payments in 2006


(828
)




(828
)Balance at March 31, 2006

$
912

$
382

$
1,294


We
expect to pay employee related benefits to certain former employees of Bone Care through the second half of 2006.

20

---



Acquisition of Verigen AG

In February 2005, we acquired Verigen AG, or Verigen, a private company based in Leverkusen, Germany with a proprietary cell therapy product for cartilage
repair (referred to as MACI) that is currently sold in Europe and Australia. We paid $11.8 million in initial cash payments and may be obligated to make additional cash payments of up to an
aggregate of approximately $38 million over the next six years, based upon the achievement of development and commercial milestones relating to regulatory approval and commercialization of MACI
in the United States, as well as contingent payments on worldwide sales of that product. We accounted for the acquisition as a purchase and accordingly, included its results of operations in our
consolidated statements of operations from February 8, 2005, the date of acquisition.

In-Process Research and Development

In connection with our acquisition of Verigen, we acquired IPR&D related to MACI, a proprietary approach to cartilage repair. As of the date of our acquisition of
Verigen, MACI, which has received marketing approvals in Europe and Australia, had not reached technological feasibility in the United States due to lack of regulatory approval and did not have an
alternative use. Accordingly, we allocated to IPR&D, and charged to expense in our consolidated statements of operations in March 2005, $9.5 million, representing the portion of the
purchase price attributable to this project in the United States.

As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $33 million to complete the development of, obtain approval
for and commercialize MACI in the United States.

Acquisition of Synvisc Sales and Marketing Rights from Wyeth

In January 2005, we consummated an arrangement with Wyeth under which we reacquired the sales and marketing rights to Synvisc in the United States, as well
as Germany, Poland, Greece, Portugal and the Czech Republic. In exchange for the sales and marketing rights, we paid initial payments totaling $121.0 million in cash to Wyeth and
$0.3 million of acquisition costs. We have also accrued contingent payments to Wyeth totaling $72.6 million, of which $63.6 million had been paid as of March 31, 2006.
Distribution rights (a component of other intangible assets, net) in our consolidated balance sheet as of March 31, 2006 include a total of $193.9 million for the initial and contingent
payments (made or accrued) as of that date. We will make a series of additional contingent payments to Wyeth based on the volume of Synvisc sales in the covered territories. These contingent payments
could extend out to June 2012, or could total a maximum of $293.7 million, whichever comes first.

We
determined that the contingent payments to Wyeth represent contingent purchase price. Accordingly, as contingent payments are made in the future, the amounts will be recorded as
additional purchase price for the underlying intangible asset. We calculate amortization expense for this intangible asset based on an economic use model, taking into account our forecasted future
sales of Synvisc and the resulting estimated future contingent payments we will be required to make. We periodically update the estimates used in this amortization calculation based on changes in
forecasted sales and resulting estimated contingent payments.

21

---



The
reacquired Synvisc distribution rights qualify as an asset rather than an acquired business. As a result, we do not provide pro forma results for our reacquisition of the Synvisc
distribution rights.

Acquisition of ILEX Oncology

In-Process Research and Development

In connection with our December 2004 acquisition of ILEX Oncology, an oncology drug development company, we acquired IPR&D related to three development
projects, Campath (alemtuzumab) for indications other than B-cell chronic lymphocytic leukemia, Clolar and tasidotin hydrochloride. As of the date of our acquisition of ILEX Oncology, none
of these projects had reached technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D, and charged to expense in our consolidated statements of operations in
December 2004, $254.5 million, representing the portion of the purchase price attributable to these projects, of which $96.9 million is attributable to the Campath (alemtuzumab)
development projects, $113.4 million is attributable to the Clolar development projects and $44.2 million is related to the tasidotin development projects. In December 2004, after
the date of our acquisition of ILEX Oncology, the FDA granted marketing approval for Clolar for the treatment of children with refractory or relapsed acute lymphoblastic leukemia.

As
of March 31, 2006, we estimated that it will take approximately two to five years and an investment of approximately $119 million to complete the development of, obtain
approval for and commercialize Campath (alemtuzumab) for non-Hodgkin's lymphoma, multiple sclerosis and other cancer and noncancer indications. We estimated that it will take approximately
two to five years and an investment of approximately $66 million to complete the development of, obtain approval for and commercialize Clolar for adult hematologic cancer, solid tumor and
additional pediatric acute leukemia indications. We estimated that it will take approximately four to six years and an investment of approximately $24 million to complete the development of,
obtain approval for and commercialize tasidotin.

Acquisition of Physician Services and Analytical Services Business Units of IMPATH

In May 2004, we acquired substantially all of the pathology/oncology testing assets related to the Physician Services and Analytical Services business
units of IMPATH, a national medical testing provider, for total cash consideration of $215.3 million, including acquisition costs. We accounted for the acquisition as a purchase and
accordingly, included the results of operations related to the acquired
business units in our consolidated statements of operations from May 1, 2004, the date of acquisition. The purchase price is subject to adjustment based upon the completion of a
post-closing assessment of the working capital of the acquired business units as of April 30, 2004.

Pro Forma Financial Summary

Pro forma results of operations are not presented for the acquisitions completed during the periods shown. We determined that the acquisitions of Bone Care and
Verigen in 2005 constitute acquisitions of businesses, however, these acquisitions did not individually or in the aggregate have a material effect on our results of operations.

22

---





6. Inventories

March 31,
2006

December 31,
2005(Amounts in thousands)Raw materials

$
85,295

$
76,466Work-in-process


89,678


90,629Finished goods


141,454


130,557Total

$
316,427

$
297,652


We
capitalize inventory produced for commercial sale, which may result in the capitalization of inventory prior to regulatory approval. If a product is not approved for sale, it would
result in the write off of the inventory and a charge to earnings. Our total inventories included $20.5 million at March 31, 2006 and $18.8 million at December 31, 2005 of
Myozyme inventory, primarily consisting of finished goods, which had not been approved for sale as of those dates. We received marketing authorization for Myozyme in the European Union in
March 2006. We will introduce Myozyme on a country-by-country basis in the European Union, as pricing and reimbursement approvals are obtained. In April 2006, the
FDA granted marketing approval for Myozyme. We expect to launch Myozyme in the United States in May 2006.

7. Goodwill and Other Intangible Assets



The following table contains the change in our goodwill during the three months ended March 31, 2006 (amounts in thousands):

As of
December 31,
2005

Adjustments

As of
March 31,
2006Renal

$
304,492

$


$
304,492Therapeutics


354,709





354,709Transplant


128,511





128,511Biosurgery


7,585





7,585Diagnostics/Genetics(1)


245,342


2


245,344Other


446,928





446,928Total

$
1,487,567

$
2

$
1,487,569


---

We
are required to perform impairment tests related to our goodwill under FAS 142, "Goodwill and Other Intangible Assets," annually, which we perform in the third quarter, and
whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. There were no such events in the three months ended March 31, 2006.

23

---





The following table contains information about our other intangible assets for the periods presented (amounts in thousands):

|                       |       | As of March 31, 2006 |           | As of December 31, 2005
|---------------------- | ----- | -------------------- | --------- | -----------------------
|
|Technology             |       | $                    | 1,504,473 |                        
|Patents                |       |                      | 183,360   |                        
|Trademarks             |       |                      | 60,227    |                        
|License fees(1)        |       |                      | 51,272    |                        
|Distribution rights(2) |       |                      | 208,356   |                        
|Customer lists(3)      |       |                      | 90,782    |                        
|Other                  |       |                      | 2,076     |                        
|                       |       |                      |           |                        
|                       | Total |                      | $         | 2,100,546              
|                       |       |                      |           |                        

---

All
of our other intangible assets are amortized over their estimated useful lives. Total amortization expense for our other intangible assets was:



24

---





The
estimated future amortization expense for other intangible assets for the remainder of fiscal year 2006, the four succeeding fiscal years and thereafter is as follows (amounts in
thousands):

Year ended December 31,

Estimated
Amortization
Expense(1,2)2006 (remaining nine months)

$
146,6882007


182,7412008


184,8942009


193,7682010


207,590Thereafter


869,366


---

8. Investments in Equity Securities

We recorded $7.9 million of gains on investments in equity securities in our consolidated statement of operations for the three months ended
March 31, 2006, including:



We
review the carrying value of each of our strategic investments in equity securities on a quarterly basis for potential impairment.

At
March 31, 2006, our stockholders' equity includes $41.3 million of unrealized gains and $1.9 million of unrealized losses related to our investments in strategic
equity securities, of which $1.6 million of the unrealized losses are related to our investment in the common stock of ViaCell, Inc., or ViaCell. The price of ViaCell's common stock
declined between July 2005 and November 2005, primarily due to the FDA's decision to temporarily halt ViaCell's phase 1 clinical trial for CB001, which was being tested for potential use in
various cancer treatments. The FDA allowed ViaCell to resume clinical testing of CB001 in December 2005. Although the market value of ViaCell's common stock has remained below our cost for the
last eight months, because ViaCell has resumed its clinical trial for CB001 and there appears to be no fundamental change in ViaCell's financial or

25

---



operational
conditions, we continue to believe that the decline in market value is considered to be temporary.

9. Joint Venture with BioMarin

We formed BioMarin/Genzyme LLC to develop and market Aldurazyme, a recombinant form of the human enzyme alpha-L-iduronidase, used to treat an LSD known as
mucopolysaccharidocis I, or MPS I. We record our portion of the income of BioMarin/Genzyme LLC in equity in income (loss) of equity method investments in our consolidated statements of
operations. Our portion of BioMarin/Genzyme LLC's net income was $3.4 million for the three months ended March 31, 2006, as compared to $0.2 million for the same period of 2005.
During the three months ended March 31, 2006, we received an $8.0 million cash distribution from BioMarin/Genzyme LLC.

Condensed
financial information for BioMarin/Genzyme LLC is summarized below (amounts in thousands):

Three Months Ended
March 31,2006

2005Revenue

$
21,332

$
15,874Gross margin


14,945


10,391Operating expenses


(8,370
)

(10,196
)Net income


6,733


255


10. Other Commitments and Contingencies

Legal Proceedings

We periodically become subject to legal proceedings and claims arising in connection with our business.

Four
lawsuits have been filed against us regarding the exchange of all of the outstanding shares of Biosurgery Stock for shares of Genzyme Stock in connection with the elimination of our
tracking stocks in July 2003. Each of the lawsuits is a purported class action on behalf of holders of Biosurgery Stock. The first case, filed in Massachusetts Superior Court in
May 2003, alleged a breach of the implied covenant of good faith and fair dealing in our charter and a breach of our board of directors' fiduciary duties. The plaintiff in this case sought an
injunction to adjust the exchange ratio for the tracking stock exchange. The Court dismissed the complaint in its entirety in November 2003. Upon appeal, the Massachusetts Appeals Court upheld
the dismissal by the Superior Court of the fiduciary duty claim, but reversed the earlier decision to dismiss the implied covenant claim. In April 2006, we filed with the Massachusetts Supreme
Judicial Court (SJC) a petition for further appellate review of the Appeals Court decision reversing the dismissal of the implied covenant claim. We are awaiting the SJC's decision. Two substantially
similar cases were filed in Massachusetts Superior Court in August and October 2003. These cases were consolidated in January 2004, and in July 2004, the consolidated case was
stayed pending disposition of a fourth case, which was filed in the U.S. District Court for the Southern District of New York in June 2003. The complaint initially alleged violations of federal
securities laws, common law fraud, and a breach of the merger agreement with Biomatrix, in addition to the state law claims contained in the other cases. The plaintiffs initially sought an adjustment
to the

26

---



exchange
ratio, the rescission of the acquisition of Biomatrix, and unspecified compensatory damages. In December 2005, the plaintiffs in this case filed an amended complaint in which they
dropped all of the claims alleged in the initial complaint relating to the initial issuance of Biosurgery Stock and the acquisition of Biomatrix, and narrowed the putative class to include only those
individuals who held Biosurgery Stock on May 8, 2003. We have filed a motion to dismiss the amended complaint and to oppose the class certification, and are awaiting a decision from the Court.
Discovery in this case has been put on hold pending resolution of these motions. We believe each of these cases is without merit and continue to defend against them vigorously.

On
March 27, 2003, the Office of Fair Trading, or OFT, in the United Kingdom issued a decision against our wholly-owned subsidiary, Genzyme Limited, finding that Genzyme Limited
held a dominant position and abused that dominant position with no objective justification by pricing Cerezyme in a way that excludes other delivery/homecare service providers from the market for the
supply of home delivery and homecare services to Gaucher patients being treated with Cerezyme. In conjunction with this decision, the OFT imposed a fine on Genzyme Limited and required modification to
its list price for Cerezyme in the United Kingdom. Genzyme Limited appealed this decision to the Competition Appeal Tribunal. On May 6, 2003, the Tribunal issued an order that stayed the OFT's
decision, but required Genzyme Limited to provide a homecare distributor a discount of 3% per unit during the appeal process. The Tribunal issued its judgment on Genzyme Limited's appeal on
March 11, 2004, rejecting portions of the OFT's decision and upholding others. The Tribunal found that the list price of Cerezyme should not be reduced, but that Genzyme Limited must negotiate
a price for Cerezyme that will allow homecare distributors an appropriate margin. The Tribunal also reduced the fine imposed by the OFT for violation of U.K. competition laws. In response to the
Tribunal's decision, we recorded an initial liability of approximately $11 million in our 2003 financial statements and additional liabilities totaling approximately $1 million during
2004 and 2005, of which approximately $6 million were paid in 2005. As of December 31, 2005 and March 31, 2006, accrued expenses in our consolidated balance sheets includes the
remaining $6 million of liabilities recorded in connection with the Tribunal's decision. Genzyme Limited and the OFT were unable to negotiate a price for Cerezyme for homecare distributors and,
as a result, on September 29, 2005, the Tribunal issued a ruling establishing the discount to be provided by Genzyme Limited to homecare distributors at 7.2%, which approximates the
figure used to calculate the initial liability of approximately $11 million we recorded in 2003, and the additional liabilities totaling approximately $1 million we recorded in 2004 and
2005. Genzyme Limited has decided not to appeal this decision. Arising out of the OFT decision, on April 5, 2006, Genzyme Limited received a damage claim from Genzyme Limited's former
distributor, Healthcare at Home. Genzyme Limited and Healthcare at Home are in negotiations to arrive at a mutually agreed upon settlement of this damage claim. We do not expect that settlement of
this damage claim will have a material impact on our financial condition or results of operations.

We
are not able to predict the outcome of the pending legal proceedings listed here, or other legal proceedings, or estimate the amount or range of any reasonably possible loss we might
incur if we do not prevail in the final, non-appealable determinations of such matters. Therefore, except for the liabilities recorded in connection with the Tribunal's decision regarding
Cerezyme pricing in the United Kingdom, we have no current accruals for these potential contingencies. We cannot provide you with assurance that the legal proceedings listed here, or other legal
proceedings, will not have a material adverse impact on our financial condition or results of operations.

27

---



11. Provision for Income Taxes

Three Months Ended
March 31,2006

2005(Amounts in thousands)Provision for income taxes

$
45,369

$
44,395Effective tax rate


31
%

32
%


Our
effective tax rate for both periods varies from the U.S. statutory tax rate as a result of:



Our
effective tax rate for the three months ended March 31, 2006 was impacted by non-deductible stock option expense.

Our
effective tax rate for the three months ended March 31, 2005 was impacted by non-deductible charges for IPR&D of $9.5 million recorded in connection with
our acquisition of Verigen.

We
are currently under IRS audits for tax years 1996 to 1999, 2002 to 2003 and in certain state and foreign jurisdictions. We believe that we have provided sufficiently for all audit
exposures and assessments. Settlement of these audits or the expiration of the statute of limitations on the assessment of income taxes for any tax year may result in an increase or reduction of
future tax provisions. Any such tax or tax benefit would be recorded upon final resolution of the audits or expiration of the applicable statue of limitations. The settlement of the 1996 to 1999 IRS
audit is expected to result in a net tax benefit of approximately $30 million to $40 million. We do not expect the settlement of certain foreign audits covering 1997 to 2004 to have a
material affect on our net tax expense. We believe
settlement of both the IRS audit and certain foreign audits will likely occur in 2006. The effects of each audit will be recorded in our financial statements upon settlement.

12. Defined Benefit Pension Plans

We have defined benefit pension plans for certain employees in countries outside the U.S. These plans are funded in accordance with requirements of the
appropriate regulatory bodies governing each plan.

28

---



The
components of net pension expense for the three months ended March 31, 2006 and 2005 are as follows (amounts in thousands):

Three Months Ended
March 31,2006

2005Service cost

$
1,025

$
780Interest cost


799


723Expected return on plan assets


(971
)

(835
)Amortization and deferral of actuarial loss


268


219Net pension expense

$
1,121

$
887


For
the three months ended March 31, 2006, we contributed $0.7 million to our pension plan in the United Kingdom. We anticipate making approximately $2 million of additional
contributions to this plan in 2006 to satisfy our annual funding obligation.

13. Segment Information

In accordance with FAS 131, "Disclosures about Segments of an Enterprise and Related Information," we present segment information in a manner consistent
with the method we use to report this information to our management. Applying FAS 131, we have five reporting segments as described in Note 1., "Description of Business," to our
financial statements included in this report.

Effective
January 1, 2006, as a result of changes in how we review our business, certain general and administrative expenses, as well as research and development expenses related
to our preclinical development programs, which were formerly allocated amongst our reporting segments and Other, are now allocated to Corporate. We have revised our 2005 segment disclosures to conform
to our 2006 presentation.

29

---



We
have provided information concerning the operations in these reporting segments in the following table (amounts in thousands):

Three Months Ended
March 31,2006

2005Revenues:Renal(1)

$
137,590

$
99,403Therapeutics(1)


345,633


315,053Transplant


34,266


31,155Biosurgery(1)


90,536


75,052Diagnostics/Genetics(1)


86,663


79,373Other


36,111


29,474Corporate(1)


43


439Total

$
730,842

$
629,949Income (loss) before income taxes:Renal(1)

$
31,798

$
34,102Therapeutics(1)


230,954


201,828Transplant


4,434


(3,618
)Biosurgery(1)


4,051


(7,778
)Diagnostics/Genetics(1)


1,106


479Other(1)


(13,393
)

(11,420
)Corporate(1,2,3)


(112,607
)

(73,640
)Total

$
146,343

$
139,953


---

Acquisition

Date Acquired

Business Segment(s)

IPR&D ChargeHernia repair assets of Surgi.B

March 30, 2006

Biosurgery

NoneGene therapy assets of Avigen

December 19, 2005

Therapeutics

$7.0 millionManufacturing operation of Cell Genesys

November 22, 2005

Therapeutics

NoneEqual Diagnostics

July 15, 2005

Diagnostics/Genetics

NoneBone Care

July 1, 2005

Renal/Corporate

$12.7 millionVerigen

February 8, 2005

Biosurgery/Corporate

$9.5 millionSynvisc sales and marketing rights from Wyeth

January 6, 2005

Biosurgery

None


30

---





We provide information concerning the assets of our reportable segments in the following table (amounts in thousands):

March 31,
2006

December 31,
2005Segment Assets(1):Renal

$
1,344,003

$
1,343,795Therapeutics


1,001,388


972,504Transplant


376,855


369,366Biosurgery


454,251


456,634Diagnostics/Genetics


471,235


474,751Other


723,973


728,773Corporate(2)


2,656,221


2,533,042Total

$
7,027,926

$
6,878,865


---

Segment
assets for Corporate consist of the following (amounts in thousands):

March 31,
2006

December 31,
2005Cash, cash equivalents, short- and long-term investments

$
1,201,083

$
1,089,102Deferred tax assetscurrent


172,173


170,443Property, plant & equipment, net


853,518


826,221Investment in equity securities


130,317


135,930Other


299,130


311,346Total

$
2,656,221

$
2,533,042


31

---





ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

When reviewing the discussion below, you should keep in mind the substantial risks and uncertainties that characterize our business. In particular, we encourage
you to review the risks and uncertainties described under "Factors Affecting Future Operating Results" below. These risks and uncertainties could cause actual results to differ materially from those
forecasted in forward-looking statements or implied by past results and trends. Forward-looking statements are statements that attempt to project or anticipate future developments in our business; we
encourage you to review the examples of forward-looking statements under "Note Regarding Forward-Looking Statements" at the beginning of this report. These statements, like all statements in this
report, speak only as of the date of this report (unless another date is indicated), and we undertake no obligation to update or revise the statements in light of future developments.

INTRODUCTION

We are a global biotechnology company dedicated to making a major impact on the lives of people with serious diseases. Our broad product and service portfolio is
focused on rare disorders, renal disease, orthopaedics, organ transplant, and diagnostic and predictive testing. We are organized into five financial reporting units, which we also consider to be our
reporting segments:



We
report the activities of our oncology, bulk pharmaceuticals, including sales of WelChol, and cardiovascular business units under the caption "Other." We report our general and
administrative operations and corporate science activities under the caption "Corporate."

Effective
January 1, 2006, as a result of changes in how we review our business, certain general and administrative expenses, as well as research and development expenses related
to our preclinical development programs, which were formerly allocated amongst our reporting segments and Other, are now allocated to Corporate. We have revised our 2005 segment disclosures to conform
to our 2006 presentation.

32

---



MERGERS AND ACQUISITIONS

Acquisition of Surgi.B

In March 2006, we acquired Surgi.B, a privately-held company based in Beauzelle, France, which owned the exclusive rights to manufacture and sell GlucaMesh and
GlucaTex, two beta glucan-coated mesh products for use in the surgical repair of inguinal hernias, for an up-front cash payment of $5.5 million. In addition, we are obligated to make certain milestone
payments totaling up to approximately $6 million and royalty payments based on future sales of GlucaMesh and GlucaTex.

Acquisition of Gene Therapy Assets from Avigen

In December 2005, we acquired certain gene therapy assets from Avigen, a publicly-traded, biopharmaceutical company based in Alameda, California with a
focus on unique small molecule therapeutics and biologics to treat serious neurological disorders, in exchange for an up-front cash payment of $12.0 million. We allocated the
purchase price to the intangible assets acquired based on their estimated fair values as of December 19, 2005, the date of acquisition. We allocated $5.0 million of the
up-front cash payment to technology in other intangible assets on our consolidated balance sheet and recorded a charge of $7.0 million to IPR&D. In addition, we may be obligated to
make up to approximately $38 million of potential milestone payments based on the development and approval of, and royalty payments based on the sale of, products developed between now and 2020
that rely on the intellectual property purchased from Avigen.

Acquisition of Equal Diagnostics

In July 2005, we acquired Equal Diagnostics, a privately-held diagnostics company in Exton, Pennsylvania, that formerly served as a distributor
for our clinical chemistry reagents. We paid $5.0 million in initial cash payments and issued promissory notes to the three former shareholders of Equal Diagnostics totaling
$10.0 million in principal and interest. These notes bear interest at 3.86% and are payable over eight years in equal annual installments commencing on March 31, 2007. In addition to
these guaranteed payments, we may be obligated to make additional cash payments of up to an aggregate of approximately $8 million during the period commencing March 31, 2007 and ending
March 31, 2014 based upon the gross margin of the acquired business, as defined in the purchase agreement. We accounted for the acquisition as a purchase and accordingly, included its results
of operations in our consolidated statements of operations from July 15, 2005, the date of acquisition.

Acquisition of Bone Care

In July 2005, we acquired Bone Care, a publicly-held specialty pharmaceutical company based in Middleton, Wisconsin with a focus on nephrology.
We paid gross consideration of $712.3 million in cash. As part of the transaction, we acquired Hectorol, a line of vitamin D2 pro-hormone products used to treat secondary
hyperparathyroidism in patients on dialysis and those with earlier stage chronic kidney disease, or CKD, which we have added to our Renal business. We accounted for the acquisition as a purchase and
accordingly, included its results of operations in our consolidated statements of operations from July 1, 2005, the date of acquisition.

Acquisition of Verigen

In February 2005, we acquired Verigen, a private company based in Leverkusen, Germany with a proprietary cell therapy product for cartilage repair
(referred to as MACI) that is currently sold in Europe and Australia. We paid $11.8 million in initial cash payments and may be obligated to make additional cash payments of up to an aggregate
of approximately $38 million over the next six years, based upon the achievement of development and commercial milestones relating to regulatory approval and commercialization of MACI in the
United States, as well as contingent payments on worldwide

33

---



sales
of that product. We accounted for the acquisition as a purchase and accordingly, included its results of operations in our consolidated statements of operations from February 8, 2005, the
date of acquisition.

The
purchase price was allocated to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The estimated
fair value of the assets acquired and liabilities assumed exceeded the initial payments by $5.7 million resulting in negative goodwill. Pursuant to FAS 142, we recorded as a liability,
contingent consideration up to the amount of the negative goodwill. If and when contingent payments come due, we will apply the payments against the contingent liability. Contingent payments in excess
of $5.7 million, if any, will be recorded as goodwill. As of March 31, 2006, we have paid $0.8 million of contingent payments, and the remaining contingent liability is
$4.9 million.

CRITICAL ACCOUNTING POLICIES AND SIGNIFICANT JUDGMENTS AND ESTIMATES

Our critical accounting policies and significant estimates are set forth under the heading "Management's Discussion and Analysis of Genzyme Corporation and
Subsidiaries' Financial Condition and Results of OperationsCritical Accounting Policies and Significant Judgments and Estimates" in Exhibit 13.1 to our 2005
Form 10-K. Excluding the addition of our policy for accounting for stock-based compensation, there have been no significant changes to our critical accounting policies and
significant judgments and estimates since December 31, 2005.

Accounting for Stock-Based Compensation

We estimate the fair value of each stock option grant using the Black-Scholes option pricing model. Use of a valuation model requires management to make certain
assumptions with respect to selected model inputs. The key assumptions in the Black-Scholes model are the risk-free interest rate, the dividend yield, the expected option life (in years) and the
expected volatility of the price of Genzyme Stock. The risk-free interest rate is based on the U.S. Treasury yield curve in effect on the date of grant. The dividend yield percentage is zero because
we do not currently pay dividends nor intend to do so during the expected option life. We use historical data on exercises of our stock options and other factors to estimate the expected option life
(in years) of the share-based payments granted. We estimate the expected volatility of our stock options and each enrollment under our ESPP based on the historical volatility of Genzyme Stock. Changes
in these input variables would affect the amount of expense associated with stock-based compensation. The compensation expense recognized for all share-based awards is net of estimated forfeitures. We
estimate forfeiture rates based on historical analysis of option forfeitures. If actual forfeitures should vary from estimated forfeitures, adjustments to stock-based compensation expense may be
required in future periods.

A. RESULTS OF OPERATIONS

The following discussion summarizes the key factors our management believes are necessary for an understanding of our consolidated financial statements.

34

---



REVENUES

The components of our total revenues are described in the following table:

Three Months Ended
March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Product revenue

$
657,335

$
563,213

17
%Service revenue


68,822


60,614

14
%Total product and service revenue


726,157


623,827

16
%Research and development revenue


4,685


6,122

(23
)%Total revenues

$
730,842

$
629,949

16
%


Product Revenue

We derive product revenue from sales of:



35

---



The
following table sets forth our product revenue on a segment basis:

|                      |                                             | Three Months Ended March 31, |        |         |        
|--------------------- | ------------------------------------------- | ---------------------------- | ------ | ------- | -------
|
|
|
|Renal:                |                                             |                              |        |         |        
|                      | Renagel (including sales of bulk sevelamer) |                              | $      | 118,655 |        
|                      | Hectorol                                    |                              |        | 18,904  |        
|                      |                                             |                              |        |         |        
|                      |                                             | Total Renal                  |        |         | 137,559
|                      |                                             |                              |        |         |        
|Therapeutics:         |                                             |                              |        |         |        
|                      | Cerezyme                                    |                              |        | 239,009 |        
|                      | Fabrazyme                                   |                              |        | 80,503  |        
|                      | Thyrogen                                    |                              |        | 22,993  |        
|                      | Other Therapeutics                          |                              |        | 2,128   |        
|                      |                                             |                              |        |         |        
|                      |                                             | Total Therapeutics           |        |         | 344,633
|                      |                                             |                              |        |         |        
|Transplant:           |                                             |                              |        |         |        
|                      | Thymoglobulin/Lymphoglobuline               |                              |        | 32,860  |        
|                      | Other Transplant                            |                              |        | 1,406   |        
|                      |                                             |                              |        |         |        
|                      |                                             | Total Transplant             |        |         | 34,266 
|                      |                                             |                              |        |         |        
|Biosurgery:           |                                             |                              |        |         |        
|                      | Synvisc                                     |                              |        | 53,263  |        
|                      | Sepra products                              |                              |        | 19,415  |        
|                      | Other Biosurgery                            |                              |        | 6,974   |        
|                      |                                             |                              |        |         |        
|                      |                                             | Total Biosurgery             |        |         | 79,652 
|                      |                                             |                              |        |         |        
|Diagnostics/Genetics: |                                             |                              |        |         |        
|                      | Diagnostics Products                        |                              |        | 29,211  |        
|                      |                                             |                              |        |         |        
|Other product revenue |                                             |                              | 32,014 |         |        
|                      |                                             |                              |        |         |        
|                      |                                             | Total product revenues       |        | $       | 657,335
|                      |                                             |                              |        |         |        

Renal

Sales of Renagel, including sales of bulk sevelamer, increased 19% to $118.7 million for the three months ended March 31, 2006, as compared to the
same period of 2005, primarily due to a $17.8 million increase in sales, of which $12.7 million is primarily attributable to increased end-user demand in the United States
and Europe, and $5.1 million is attributable to a 9.5% price increase for Renagel, which became effective in December 2005. The average exchange rate for the Euro against the U.S. dollar
decreased 8% in the three months ended March 31, 2006, as compared to the same period of 2005, negatively impacting Renagel revenue by $3.0 million for the three months ended
March 31, 2006. However, an 18% decrease in the average exchange rate for the Brazilian Real against the U.S. dollar for the three months ended March 31, 2006, as compared to the same
period in 2005, positively impacted Renagel revenue by $1.6 million. Sales of Renagel, including sales of bulk sevelamer, were 18% of our total product revenue for the three months ended
March 31, 2006 and 2005.

Our
acquisition of Bone Care on July 1, 2005 expanded our Renal product offerings with the addition of Hectorol, a complimentary product to Renagel used to treat secondary
hyperparathyroidism

36

---



in
patients on dialysis and those with earlier stage CKD. Bone Care's operations are integrated into our Renal business, and our sales representatives have begun selling Hectorol to nephrologists in
the United States. Sales of Hectorol were $18.9 million for the three months ended March 31, 2006.

We
conducted a 2,100-patient post-marketing study of Renagel called the DCOR trial, which evaluated the ability of Renagel to improve patient morbidity and
mortality and compared Renagel to calcium-based phosphate binders with respect to overall morbidity and mortality. We released top-line data from this trial in July 2005 and
presented the data at the American Society of Nephrology meeting in November 2005. The study did not meet its primary end point of a statistically significant reduction in mortality from all
causes. However, in a pre-specified sub-group analysis, Renagel demonstrated a significant reduction in mortality from all causes in patients 65 years of age or older
and in patients using Renagel for two years or more. We expect to receive morbidity data from the Centers for Medicare and Medical Services, or CMS, in mid 2006 and may present such data later this
year.

We
expect sales of Renagel and Hectorol to increase, driven primarily by growing patient access to our products and the continued adoption of the products by nephrologists worldwide. We
expect adoption rates for Renagel to trend favorably as a result of the DCOR trial and the growing acceptance of the National Kidney Foundation's 2003 Kidney Disease Outcome Quality Initiative, or
K/DOQI, Guidelines for Bone Metabolism and Disease in CKD. Renagel and Hectorol compete with several other products and our future sales may be impacted negatively by these products. We discuss these
competitors under the heading "Factors Affecting Future Operating ResultsOur future success will depend on our ability to effectively develop and market our products and services against
those of our competitors" in this report. In addition, our ability to continue to increase sales of Renagel and Hectorol will depend on many other factors, including our ability to optimize dosing and
improve patient compliance with dosing of Renagel, the availability of reimbursement from third-party payors and the extent of coverage, including under the Medicare Prescription Drug Improvement and
Modernization Act, and the accuracy of our estimates of fluctuations in the payor mix. Also our ability to effectively manage wholesaler inventories and the levels of compliance with the inventory
management programs we implemented for Renagel and Hectorol with our wholesalers could impact the revenue from our Renal reporting segment that we record from period to period.

Therapeutics

Therapeutics product revenue increased 10% to $344.6 million for the three months ended March 31, 2006, as compared to the same period of 2005, due
to continued growth in sales of Cerezyme, Fabrazyme and Thyrogen.

The
6% growth in sales of Cerezyme to $239.0 million for three months ended March 31, 2006, as compared to the same period of 2005, is attributable to our continued
identification of new Gaucher disease patients, particularly in international markets. Our price for Cerezyme has remained consistent from period to period. Although we expect Cerezyme to continue to
be a substantial contributor to revenues in the future, it is a mature product, and as a result, we do not expect that the current new patient growth trend will continue. The average exchange rate for
the Euro against the U.S. dollar decreased 8% during the three months ended March 31, 2006, as compared to the same period of 2005, negatively impacting sales of Cerezyme by
$7.0 million.

Our
results of operations are highly dependent on sales of Cerezyme and a reduction in revenue from sales of this product would adversely affect our results of operations. Sales of
Cerezyme are approximately 36% of our total product revenue for the three months ended March 31, 2006, as compared to 40% for the same period of 2005. Revenue from Cerezyme would be impacted
negatively if competitors developed alternative treatments for Gaucher disease, and the alternative products gained commercial acceptance, if our marketing activities are restricted, or if coverage,
pricing or reimbursement is limited. Although orphan drug status for Cerezyme, which provided us with exclusive

37

---



marketing
rights for Cerezyme in the United States for seven years, expired in May 2001, we continue to have patents protecting our method of manufacturing Cerezyme until 2010 and the
composition of Cerezyme as made by that process until 2013. The expiration of market exclusivity and orphan drug status will likely subject Cerezyme to increased competition, which may decrease the
amount of revenue we receive from this product or the growth of that revenue. We are aware of companies that have initiated efforts to develop competitive products, and other companies may do so in
the future. We discuss these competitors under the heading "Factors Affecting Future Operating ResultsOur future success will depend on our ability to effectively develop and market our
products and services against those of our competitors" in this report.

The
15% increase to $80.5 million for the three months ended March 31, 2006 in sales of Fabrazyme, as compared to the same period of 2005, is primarily attributable to
increased patient identification worldwide as Fabrazyme is introduced into new markets. The 8% decrease in the average exchange rate for the Euro against the U.S. dollar negatively impacted sales of
Fabrazyme by $2.0 million.

Sales
of Thyrogen increased 30% to $23.0 million for the three months ended March 31, 2006, as compared to the same period of 2005, due to worldwide volume growth which
impacted sales by $2.4 million and a 10% increase in price, impacting sales by $1.2 million. The decrease in the average exchange rate of the Euro against the U.S. dollar did not have a
material impact on the sales of Thyrogen.

We
submitted marketing applications for Myozyme in the European Union in December 2004 and in the United States in July 2005. In December 2005, the European
Committee for Human Services unanimously recommended full approval of Myozyme and subsequently, in March 2006, we received marketing authorization for Myozyme in the European Union. We will
introduce Myozyme on a country-by-country basis in the European Union, as pricing and reimbursement approvals are obtained. In April 2006, the FDA granted marketing
approval for Myozyme. We expect to launch Myozyme in the United States in May 2006. Myozyme has received orphan drug designation in the United States, which provides seven years of market
exclusivity. We plan to submit a marketing application for Myozyme in Japan later this year.

We
currently manufacture Myozyme in the United States. In the future, we expect to also produce Myozyme at our new protein manufacturing facility in Geel, Belgium, and our new
fill/finish facility in
Waterford, Ireland, to ensure that we are able to meet the anticipated demand for the product throughout the world.

Transplant

Transplant's product revenue increased 10% to $34.3 million for the three months ended March 31, 2006 as compared to the same period of 2005. The
increase is primarily due to a $6.2 million increase in sales of Thymoglobulin as a result of increased utilization of Thymoglobulin in transplant procedures. This increase was partially offset
by a $1.8 million decrease in revenue from a license agreement with Proctor & Gamble Pharmaceuticals, Inc., or PGP, a subsidiary of The Proctor and Gamble Company, in the first
quarter of 2005, for which there is no comparable amount in the same period of 2006. In December 2005, PGP exercised its option to terminate an agreement under which we had granted PGP an
exclusive, worldwide license to develop and market RDP58 for the treatment of gastrointestinal and other disorders.

We
expect sales of Thymoglobulin to increase, driven primarily by our continued entry into new geographical markets, together with an overall growth in solid organ and living donor renal
transplants. Thymoglobulin competes with several other products and our future sales may be impacted negatively by these products. We discuss these competitors under the heading "Factors Affecting
Future Operating

38

---



ResultsOur
future success will depend on our ability to effectively develop and market our products and services against those of our competitors" in this report.

Biosurgery

Biosurgery product revenue increased 19% to $79.7 million for the three months ended March 31, 2006, as compared to the same period of 2005. The
increase is partially attributable to the $2.8 million increase in sales of our Sepra products. In particular, sales of Seprafilm increased by $1.9 million, primarily due to an 11% price
increase in the three months ended March 31, 2006, as compared to the same period of 2005. This increase is also attributable to greater penetration into the U.S. market. Additionally, there
was a $9.2 million increase in sales of Synvisc, primarily due to a full quarter of selling Synvisc direct in the United States as compared to a partial quarter in 2005. We reacquired the
Synvisc sales and marketing rights from Wyeth in January 2005 in certain countries. We are aware of several products that compete with Synvisc, several companies that have initiated efforts to
develop competitive products and several companies that market products designed to relieve the pain of osteoarthritis. These products could have an adverse effect on future sales of Synvisc. We
discuss these competitors under the heading "Factors Affecting Future Operating ResultsOur future
success will depend on our ability to effectively develop and market our products and services against those of our competitors" included in this report.

Diagnostics/Genetics

Diagnostics/Genetics product revenue increased 9% to $29.2 million for the three months ended March 31, 2006, as compared to the same period of
2005. The increase is attributable to a 19%, or $2.9 million, increase in sales of clinical chemistry reagents resulting from our acquisition of Equal Diagnostics in July 2005.

Other Product Revenue

Other product revenue increased 32% to $32.0 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily
due to a 35% increase, to $22.3 million, in sales of bulk pharmaceuticals, including WelChol. This increase is primarily due to a 93% increase to $8.9 million of bulk sales of and
royalties earned on WelChol due to an increased demand from our U.S. marketing partner, Sankyo Pharma, Inc.

Service Revenue

We derive service revenues primarily from the following principal sources:



39

---





The
following table sets forth our service revenue on a segment basis:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Renal

$
31

$


N/ABiosurgery


10,880


7,950

37
%Diagnostics/Genetics


57,452


52,507

9
%Other service revenue


459


157

192
%Total service revenue

$
68,822

$
60,614

14
%


Service
revenue attributable to our Biosurgery segment increased 37% to $10.9 million in the three months ended March 31, 2006 as compared to the same period of 2005. The
increase is primarily due to a full quarter of MACI sales during the first quarter of 2006, as compared to a partial quarter of sales during the same period of 2005. We acquired MACI in the Verigen
transaction in February 2005.

Service
revenue attributable to our Diagnostics/Genetics reporting segment increased 9% to $57.5 million in the three months ended March 31, 2006, as compared to the same
period of 2005. This increase is primarily attributable to:



International Product and Service Revenue

A substantial portion of our revenue was generated outside of the United States. The following table provides information regarding the change in international
product and service revenue as a percentage of total product and service revenue during the periods presented:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)International product and service revenue

$
326,680

$
290,291

13
%% of total product and service revenue


45
%

47
%


The
13% increase to $326.7 million for the three months ended March 31, 2006 in international product and service revenue, as compared to the same period of 2005, is
primarily due to a $30.4 million increase in the combined international sales of Renagel, Cerezyme, Fabrazyme, Thyrogen, Synvisc and Campath primarily due to an increase in the number of
patients using these products in countries outside of the United States. Additionally, sales from third-party shipments to countries outside the United States increased by $9.8 million
primarily due to a $7.9 million increase in sales from third-party shipments of Cerezyme to Argentina and Brazil. The average exchange rate for the Euro against the U.S. dollar decreased 8%
during the three months ended March 31, 2006, as compared to the same period of 2005, negatively impacting total product and service revenue by $15.4 million.

International
product and service revenue as a percentage of total product and service revenue decreased 2% during the three months ended March 31, 2006, as compared to the same
period of 2005. This was primarily due to the increase in total domestic revenue as a result of our acquisitions of Equal Diagnostics and Bone Care in July 2005, as well as the reacquisition of
the sales and marketing rights to Synvisc in the United States in January 2005.

40

---



Research and Development Revenue

The following table sets forth our research and development revenue on a segment basis:

Three Months Ended
March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Therapeutics

$
1,000

$
554

81
%Transplant





17

(100
)%Biosurgery


4


134

(97
)%Other


3,638


4,978

(27
)%Corporate


43


439

(90
)%Total research and development revenue

$
4,685

$
6,122

(23
)%


Total
research and development revenue decreased $1.4 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to less
research and development work related to Campath performed on behalf of Schering AG, under agreements we assumed in connection with our acquisition of ILEX Oncology in December 2004.

MARGINS

The components of our total margins are described in the following table:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Product margin

$
536,823

$
458,239

17
%% of total product revenue


82
%

81
%Service margin

$
22,384

$
19,495

15
%% of total service revenue


33
%

32
%Total product and service margin

$
559,207

$
477,734

17
%% of total product and service revenue


77
%

77
%


Product Margin

Our overall product margin increased $78.6 million, or 17%, for the three months ended March 31, 2006, as compared to the same period of 2005. This
is primarily due to:



The
amortization of product related intangible assets is included in amortization expense and, as a result, is excluded from cost of products sold and the determination of product
margins.

41

---



Service Margin

Our overall service margin increased $2.9 million, or 15%, for the three months ended March 31, 2006, as compared to the same period of 2005. This
is primarily due to a $2.9 million, or 37%, increase in the sales of Biosurgery services as well as a $4.9 million, or 9%, increase in sales of Diagnostics/Genetics services. Total
service margin as a percent of total revenue increased in the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to increased sales of higher margin
Biosurgery services such as MACI. Diagnostics/Genetics service margin as a percent of total revenue remained relatively consistent in the three months ended March 31, 2006, as compared to the
same period of 2005.

OPERATING EXPENSES

Selling, General and Administrative Expenses

Effective January 1, 2006, as a result of changes in how we review our business, certain general and administrative expenses, which were formerly allocated
amongst our reporting segments and Other, are now allocated to Corporate. We have revised our 2005 segment disclosures to conform to our 2006 presentation.

The
following table provides information regarding the change in selling, general and administrative expenses, or SG&A, during the periods presented:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Selling, general and administrative expenses

$
230,669

$
181,839

27
%


SG&A
increased $48.8 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to:



SG&A
was 32% of total revenue for the three months ended March 31, 2006 and 29% for the same period of 2005. In 2006, we expect SG&A as a percentage of total revenue to be
consistent with 2005, primarily due to the launch of Myozyme in Europe and the United States in 2006 and increased marketing support for Synvisc.

Research and Development Expenses

Effective January 1, 2006, as a result of changes in how we review our business, certain research and development expenses related to our preclinical
development portfolios, which were formerly allocated amongst our reporting segments and Other, are now allocated to Corporate. We have revised our 2005 segment disclosures to conform to our 2006
presentation.

42

---



The
following table provides information regarding the change in research and development expense during the periods presented:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Research and development expenses

$
152,323

$
114,745

33
%


Research
and development expenses increased $37.6 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to:



These
increases were partially offset by decreases of:



Amortization of Intangibles

The following table provides information regarding the change in amortization of intangibles expense during the periods presented:

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Amortization of intangibles

$
52,692

$
41,186

28
%


Amortization
of intangibles expense increased by $11.5 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to
additional amortization expense attributable to the intangible assets acquired in connection with our acquisitions of Bone Care

43

---



and
Equal Diagnostics in July 2005 and Verigen in February 2005, as well as the reacquisition of the Synvisc sales and marketing rights from Wyeth in January 2005.

As
discussed in Note 5., "Mergers and Acquisitions," to our financial statements included in this report, we calculate amortization expense for the Synvisc sales and marketing
rights we reacquired from Wyeth by taking into account forecasted future sales of Synvisc and the resulting future contingent payments we will be required to make to Wyeth, which will be recorded as
intangible assets when the payments are accrued. In addition, we calculate the amortization expense for the license fees paid for GlucaMesh and GlucaTex based on forecasted future sales of these
products and the resulting future contingent payments we will be required to make to the former shareholders of Surgi.B, which will be recorded as intangible assets when the payments are accrued. As a
result, we expect amortization of intangibles to increase over the next five years based on these future contingent payments.

Purchase of In-Process Research and Development

In connection with four of our acquisitions since 2004, we have acquired various IPR&D projects. Substantial additional research and development will be required
prior to any of our acquired IPR&D programs and technology platforms reaching technological feasibility. In addition, once research is completed, each product candidate acquired from Avigen, Bone
Care, Verigen and ILEX Oncology will need to complete a series of clinical trials and receive FDA or other regulatory approvals prior to commercialization. Our current estimates of the time and
investment required to develop these products and technologies may change depending on the different applications that we may choose to pursue. We cannot give assurances that these programs will ever
reach feasibility or develop into products that can be marketed profitably. In addition, we cannot guarantee that we will be able to develop and commercialize products before our competitors develop
and commercialize products for the same indications. If products based on our acquired IPR&D programs and technology platforms do not become commercially viable, our results of operations could be
materially adversely affected.

Avigen

In connection with our acquisition of certain gene therapy assets from Avigen, we acquired IPR&D related to Avigen's Parkinson's disease program.

As
of the date this transaction closed, this program had not reached technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D and charged to
expense in our consolidated statements of operations in March 2006, $7.0 million, representing the portion of the $12.0 million up-front payment to Avigen attributable
to the Parkinson's disease program.

As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $74 million to complete the development of, obtain approval
for and commercialize a product arising from the acquired Parkinson's disease program.

Bone Care

In connection with our acquisition of Bone Care, we acquired IPR&D related to LR-103, a vitamin D therapeutic candidate that is an active metabolite
of Hectorol. In biological models, this product candidate is readily absorbed after oral delivery and circulates through the bloodstream to tissues which respond to vitamin D hormones. Bone Care
conducted early stage research of LR-103 in a variety of indications.

As
of the date this transaction closed, this project had not reached technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D and charged to
expense in our consolidated statements of operations in September 2005, $12.7 million, representing the portion of the purchase price attributable to this project.

44

---



As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $15 million to complete the development of, obtain approval
for and commercialize LR-103.

Verigen

In connection with our acquisition of Verigen, we acquired IPR&D related to MACI, a proprietary approach to cartilage repair. As of the date of our acquisition of
Verigen, MACI, which has received marketing approvals in Europe and Australia, had not reached technological feasibility in the United States due to lack of regulatory approval and did not have an
alternative use. Accordingly, we allocated
to IPR&D, and charged to expense in our consolidated statements of operations in March 2005, $9.5 million, representing the portion of the purchase price attributable to this project in
the United States.

As
of March 31, 2006, we estimated that it will take approximately six years and an investment of approximately $33 million to complete the development of, obtain approval
for and commercialize MACI in the United States.

ILEX Oncology

In connection with our December 2004 acquisition of ILEX Oncology, we have acquired IPR&D related to three development projects, Campath (alemtuzumab) for
indications other than B-cell chronic lymphocytic leukemia, Clolar and tasidotin hydrochloride. As of the date of our acquisition of ILEX Oncology, none of these projects had reached
technological feasibility nor had an alternative future use. Accordingly, we allocated to IPR&D, and charged to expense in our consolidated statements of operations in December 2004,
$254.5 million, representing the portion of the purchase price attributable to these projects, of which $96.9 million is attributable to the Campath (alemtuzumab) development projects,
$113.4 million is attributable to the Clolar development projects and $44.2 million is related to the tasidotin development projects. In December 2004, after the date of our
acquisition of ILEX Oncology, the FDA granted marketing approval for Clolar for the treatment of children with refractory or relapsed acute lymphoblastic leukemia.

As
of March 31, 2006, we estimated that it will take approximately two to five years and an investment of approximately $117 million to complete the development of, obtain
approval for and commercialize Campath (alemtuzumab) for non-Hodgkin's lymphoma, multiple sclerosis and other cancer and noncancer indications. We estimated that it will take approximately
two to five years and an investment of approximately $65 million to complete the development of, obtain approval for and commercialize Clolar for adult hematologic cancer, solid tumor and
additional pediatric acute leukemia indications. We estimated that it will take approximately four to six years and an investment of approximately $24 million to complete the development of,
obtain approval for and commercialize tasidotin.

45

---



OTHER INCOME AND EXPENSES

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Equity in income (loss) of equity method investments

$
2,246

$
(1,718
)
(231
)%Minority interest


2,446


2,194

11
%Gains on investments in equity securities


7,942


141

5,533
%Other


(139
)

(60
)
132
%Investment income


10,078


6,618

52
%Interest expense


(4,438
)

(3,808
)
17
%Total other income

$
18,135

$
3,367

439
%


Equity in Income (Loss) of Equity Method Investments

Under this caption, we record our portion of the results of our joint ventures with BioMarin, Diacrin, Inc. and Medtronic, Inc., and our investments
in Peptimmune, Inc. and Therapeutic Human Polyclonals, Inc., which we refer to as THP.

Equity
in loss of equity method investments decreased $4.0 million, or 231%, due primarily to $3.4 million of income we recorded for the three months ended March 31,
2006, as compared to income of $0.2 million for the comparable period of 2005. The $3.4 million of income represents our portion of the net income of BioMarin/Genzyme LLC as a result of
increased sales of Aldurazyme.

Minority Interest

As a result of our application of FASB Interpretation No., or FIN, 46, "Consolidation of Variable Interest Entities," we have consolidated the results of
Dyax-Genzyme LLC and Excigen Inc. Our consolidated balance sheet as of March 31, 2006, includes assets related to Dyax-Genzyme LLC, which are not significant, and
substantially all of which are lab equipment net of their associated accumulated depreciation. We have recorded Dyax's portion of this joint venture's losses as minority interest in our consolidated
statements of operations. The results of Excigen are not significant.

Gains on Investments in Equity Securities

Gains on investments in equity securities for the three months ended March 31, 2006 includes:



There
are no comparable amounts for these gains in the same period of 2005.

We
review the carrying value of each of our strategic investments in equity securities on a quarterly basis for potential impairment.

At
March 31, 2006, our stockholders' equity includes $41.3 million of unrealized gains and $1.9 million of unrealized losses related to our investments in strategic
equity securities, of which $1.6 million of the unrealized losses are related to our investment in the common stock of ViaCell. The price of ViaCell's common stock declined between July 2005
and November 2005, primarily due to the

46

---



FDA's
decision to temporarily halt ViaCell's phase 1 clinical trial for CB001, which was being tested for potential use in various cancer treatments. The FDA allowed ViaCell to resume clinical testing
of CB001 in December 2005. Although the market value of ViaCell's common stock has remained below our cost for the last eight months, because ViaCell has resumed its clinical trial for CB001 and there
appears to be no fundamental change in ViaCell's financial or operational conditions, we continue to believe that the decline in market value is considered to be temporary.

Investment Income

Our investment income increased 52% to $10.1 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to an
increase in the average portfolio yield and higher average cash balances. This increase was offset, in part, by an increase in the realized losses on our U.S. investment portfolio.

Interest Expense

Our interest expense increased 17% to $4.4 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due
to a $0.9 million decrease in capitalized interest due to manufacturing plant completions.

Provision for Income Taxes

Three Months Ended March 31,Increase/
(Decrease)
% Change2006

2005(Amounts in thousands)Provision for income taxes

$
45,369

$
44,395

2
%Effective tax rate


31%


32%


Our
effective tax rate for both periods varies from the U.S. statutory tax rate as a result of:



Our
effective tax rate for the three months ended March 31, 2006 was impacted by non-deductible stock option expense.

Our
effective tax rate for the three months ended March 31, 2005 was impacted by non-deductible charges for IPR&D of $9.5 million recorded in connection with
our acquisition of Verigen.

We
are currently under IRS audits for tax years 1996 to 1999, 2002 to 2003 and in certain state and foreign jurisdictions. We believe that we have provided sufficiently for all audit
exposures and assessments. Settlement of these audits or the expiration of the statute of limitations on the assessment of income taxes for any tax year may result in an increase or reduction of
future tax provisions. Any such tax or tax benefit would be recorded upon final resolution of the audits or expiration of the applicable statue of limitations. The settlement of the 1996 to 1999 IRS
audit is expected to result in a net tax benefit of approximately $30 million to $40 million. We do not expect the settlement of certain foreign audits covering 1997 to 2004 to have a
material affect on our net tax expense. We believe

47

---



settlement
of both the IRS audit and certain foreign audits will likely occur in 2006. The effects of each audit will be recorded in our financial statements upon settlement.

B. LIQUIDITY AND CAPITAL RESOURCES

We continue to generate cash from operations. At March 31, 2006, we had cash, cash equivalents and short- and long-term investments of
$1.2 billion, an increase of $0.1 billion from cash, cash equivalents and short- and long-term investments of $1.1 billion at December 31, 2005.

The
following is a summary of our statements of cash flows for the three months ended March 31, 2006 and 2005.

Cash Flows from Operating Activities

Cash flows from operating activities are as follows (amounts in thousands):

|                                      |                                                                                                                                                                                                      | Three Months Ended
March 31,         |  
|------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------ | -
|
|Cash flows from operating activities: |                                                                                                                                                                                                      |                                      |  
|                                      | Net cash provided by operating activities before stock-based compensation, tax benefit of employee stock compensation, excess tax benefits from stock-based compensation and working capital changes |                                      | $
|                                      | Stock-based compensation                                                                                                                                                                             |                                      |  
|                                      | Tax benefit of employee stock compensation                                                                                                                                                           |                                      |  
|                                      | Excess tax benefits from stock-based compensation                                                                                                                                                    |                                      |  
|                                      | Increase (decrease) in cash from working capital changes (excluding impact of acquired assets and assumed liabilities)                                                                               |                                      |  
|                                      |                                                                                                                                                                                                      |                                      |  
|                                      |                                                                                                                                                                                                      | Cash flows from operating activities |  
|                                      |                                                                                                                                                                                                      |                                      |  

Cash
provided by operating activities decreased $20.5 million for the three months ended March 31, 2006, as compared to the same period of 2005, primarily due to a
$19.9 million decrease in cash from working capital changes. Cash flows from operating activities for the three months ended March 31, 2006 includes $32.6 million of stock-based
compensation expense, which was recorded in connection with our adoption of FAS 123R and for which there was no similar amount in the same period of 2005.
In connection with our adoption of FAS 123R, we were also required to change the classification in our consolidated statements of cash flows of any tax benefits realized upon the exercise of
stock options in excess of that which is associated with the expense recognized for financial reporting purposes. For the three months ended March 31, 2006, $2.9 million of excess tax benefits
from stock-based compensation were presented as a financing cash inflow rather than as a reduction of income taxes paid in our consolidated statement of cash flows for which there were no similar
amounts in the same period of 2005. We adopted FAS 123R using the modified prospective transition method and as a result, we have not restated our results for the three months ended
March 31, 2005 to reflect the adoption of this standard.

48

---



Cash Flows from Investing Activities

Cash flows from investing activities are as follows (amounts in thousands):

|                                      |                                                                          | Three Months Ended
March 31,         |  
|------------------------------------- | ------------------------------------------------------------------------ | ------------------------------------ | -
|
|Cash flows from investing activities: |                                                                          |                                      |  
|                                      | Net purchases of investments, including investments in equity securities |                                      | $
|                                      | Proceeds from sales of investments in equity securities                  |                                      |  
|                                      | Purchases of property, plant and equipment                               |                                      |  
|                                      | Distributions from equity investees                                      |                                      |  
|                                      | Purchases of intangible assets                                           |                                      |  
|                                      | Acquisitions, net of acquired cash                                       |                                      |  
|                                      | Acquisition of sales and marketing rights                                |                                      |  
|                                      | Other investing activities                                               |                                      |  
|                                      |                                                                          |                                      |  
|                                      |                                                                          | Cash flows from investing activities |  
|                                      |                                                                          |                                      |  

For
the three months ended March 31, 2006, capital expenditures, net purchases of investments, including investments in equity securities, and acquisitions accounted for
significant cash outlays for investing activities. For the three months ended March 31, 2006, we used:



These
decreases in cash were partially offset by $26.4 million of net cash proceeds received from sales of certain of our investments in equity securities, of which $24.4 million is
attributable to the sale of our entire investment of 2.1 million shares in the common stock of BioMarin in January 2006, and an $8.0 million cash distribution from our joint
venture with BioMarin.

For
the three months ended March 31, 2005, acquisitions, net purchases of investments and capital expenditures accounted for significant cash outlays for investing activities. For
the three months ended March 31, 2005, we used:



49

---





Cash Flows from Financing Activities

Our cash flows from financing activities are as follows (amounts in thousands):

|                                      |                                                   | Three Months Ended
March 31,         |  
|------------------------------------- | ------------------------------------------------- | ------------------------------------ | -
|
|Cash flows from financing activities: |                                                   |                                      |  
|                                      | Proceeds from issuance of common stock            |                                      | $
|                                      | Excess tax benefits from stock-based compensation |                                      |  
|                                      | Payment of debt and capital lease obligations     |                                      |  
|                                      | Bank overdraft                                    |                                      |  
|                                      | Minority interest contributions                   |                                      |  
|                                      | Other financing activities                        |                                      |  
|                                      |                                                   |                                      |  
|                                      |                                                   | Cash flows from financing activities |  
|                                      |                                                   |                                      |  

For
the three months ended March 31, 2006, cash flows from financing activities increased $39.8 million, as compared to the same period of 2005, primarily due to a
$100.2 million decrease in cash used for the payment of debt and capital lease obligations, which was offset in part by a $57.0 million decrease in cash proceeds from the issuance
of common stock. Cash used for the payment of debt and capital lease obligations for the three months ended March 31, 2005 includes the repayment of $100.0 million in principal drawn
under our revolving credit facility for which there are no similar repayments in the same period of 2006. As described above, in connection with our adoption of FAS 123R effective
January 1, 2006, the $2.9 million of excess tax benefits from stock-based compensation are shown as a cash inflow in cash from financing activities for the three months ended
March 31, 2006. Because we adopted FAS 123R using the modified prospective transition method, we have not adjusted the presentation of our statement of cash flows for the three months
ended March 31, 2005, to reflect this change.

Revolving Credit Facility

In December 2003, we entered into a three year $350.0 million revolving credit facility, maturing in December 2006. As of December 31,
2005 and March 31, 2006, no amounts were outstanding under our revolving credit facility. Borrowings under this credit facility bear interest at LIBOR plus an applicable margin. The terms of
our revolving credit facility include various covenants, including financial covenants that require us to meet minimum liquidity and interest coverage ratios and to meet maximum leverage ratios. We
currently are in compliance with these covenants. We intend to refinance our revolving credit facility prior to its expiration in December 2006.

Contractual Obligations

The disclosure of payments we have committed to make under our contractual obligations is set forth under the heading "Management's Discussion and Analysis of
Genzyme Corporation and Subsidiaries' Financial Condition and Results of OperationsLiquidity and Capital Resources" in Exhibit 13.1 to our 2005 Form 10-K.
Excluding additional contingent payments to Wyeth for the reacquisition of the Synvisc sales and marketing rights, and to the former shareholders of Surgi.B related to our acquisition of the rights to
GlucaMesh and GlucaTex, as described above, there have been no material changes to our contractual obligations since December 31, 2005.

Financial Position

We believe that our available cash, investments and cash flows from operations will be sufficient to fund our planned operations and capital requirements for the
foreseeable future. Although we currently

50

---



have
substantial cash resources and positive cash flow, we have used or intend to use substantial portions of our available cash and may make additional borrowings under our revolving credit facility
for:



Our
cash reserves may be further reduced to pay principal and interest on the $690.0 million in principal under our 1.25% convertible senior notes due December 1, 2023. The
notes are initially convertible into Genzyme Stock at a conversion price of approximately $71.24 per share. Holders of the notes may require us to repurchase all or any part of the notes for cash,
common stock, or a combination, at our option, on December 1, 2008, 2013 or 2018, at a price equal to 100% of the principal amount of the notes plus accrued and unpaid interest through the date
prior to the date of repurchase. Additionally, upon a change of control, each holder may require us to repurchase for cash, at 100% of the principal amount of the notes plus accrued interest, all or a
portion of the holder's notes. On or after December 1, 2008, we may redeem for cash at 100% of the principal amount of the notes plus accrued interest, all or part of the notes that have not
been previously converted or repurchased.

In
addition, we have several outstanding legal proceedings. Involvement in investigations and litigation can be expensive and a court may ultimately require that we pay expenses and
damages. As a result of legal proceedings, we also may be required to pay fees to a holder of proprietary rights in order to continue certain operations. We have provided you detail on certain pending
legal proceedings in the notes to our consolidated financial statements.

To
satisfy these and other commitments, we may have to obtain additional financing. We cannot guarantee that we will be able to obtain any additional financing, extend any existing
financing arrangement, or obtain either on favorable terms.

Off-Balance Sheet Arrangements

We do not use special purpose entities or other off-balance sheet financing arrangements. We enter into guarantees in the ordinary course of business
related to the guarantee of our own performance and the performance of our subsidiaries. In addition, we have joint ventures and certain other arrangements that are focused on research, development,
and the commercialization of products. Entities falling within the scope of FIN 46 are included in our consolidated statements of operations if we qualify as the primary beneficiary. Entities not
subject to consolidation under FIN 46 are accounted for under the equity method of accounting if our ownership percent exceeds 20% or if we exercise significant influence over the entity. We account
for our portion of the income/losses of these entities in the line item "Equity in income (loss) of equity method investments" in our statements of operations. We also acquire companies in which we
agree to pay contingent consideration based on attaining certain thresholds.

Recent Accounting Pronouncements

FAS 151, "Inventory Costs, an amendment of ARB No. 43, Chapter 4."In November 2004, the FASB issued
FAS 151, "Inventory Costs, an amendment of ARB No. 43, Chapter 4," which clarifies that abnormal amounts of idle facility expense, freight, handling costs and wasted material (spoilage)

51

---



should
be recognized as current period charges in all circumstances. Our adoption of FAS 151, effective January 1, 2006, did not have a material impact on our financial position or
results of operations.

FAS 154, "Accounting Changes and Error Corrections, a replacement of APB Opinion No. 20 and FASB Statement No. 3."In
May 2005, the FASB issued FAS 154, "Accounting Changes and Error Corrections, a replacement of APB Opinion No. 20 and FASB Statement No. 3." FAS 154 applies to all
voluntary changes in the accounting for and reporting of changes in accounting principles and requires retrospective application to prior periods' financial statements of a voluntary change in
accounting principles unless it is not practical to do so. APB Opinion No. 20, "Accounting Changes," previously required that most voluntary changes in accounting principles be recognized by
including in net income (loss), for the period of the change, the cumulative effect of changing to the new accounting principle. FAS 154 also requires that a change in depreciation,
amortization, or depletion method for long-lived non-financial assets be accounted for as a change in accounting estimate affected by a change in accounting principle.
FAS 154 is effective for accounting changes and corrections of errors made in fiscal years beginning after December 15, 2005. Our adoption of FAS 154, effective January 1,
2006, did not impact our financial position or results of operations.

FSP Nos. FAS 115-1 and FAS 124-1, "The Meaning of Other-Than-Temporary Impairment and Its
Application to Certain Investments."In November 2005, the FASB issued FSP Nos. FAS 115-1 and FAS 124-1, "The Meaning of
Other-Than-Temporary Impairment and Its Application to Certain Investments." FSP Nos. FAS 115-1 and FAS 124-1 address the determination as
to when an investment is considered impaired, whether that impairment is other than temporary, and the measurement of an impairment loss. The FSPs also include accounting considerations subsequent to
the recognition of an other-than-temporary impairment and requires certain disclosures about unrealized losses that have not been recognized as
other-than-temporary impairments. The guidance in the FSPs clarify FAS 115, "Accounting for Certain Investments in Debt and Equity Securities," FAS 124,
"Accounting for Certain Investments Held by Not-for-Profit Organizations," and APB Opinion No. 18, "The Equity Method of Accounting for Investments in Common Stock." We
reviewed the guidance provided in FSP Nos. FAS 115-1 and FAS 124-1 and have determined that our current practices are consistent with the guidance included in the
FSPs. As a result, our adoption of the FSPs, effective January 1, 2006, did not impact our financial position and results of operations.

FAS 155, "Accounting for Certain Hybrid Financial Instrumentsan amendment of FASB Statements No. 133 and 140."In February 2006, the FASB issued FAS 155, "Accounting for Certain Hybrid Financial Instrumentsan amendment of FASB Statements No. 133 and 140," which permits a fair
value remeasurement for any hybrid financial instrument that contains an embedded derivative that would otherwise require bifurcation. This accounting standard is effective as of the beginning of
fiscal years beginning after September 15, 2006. We have not yet determined the effect, if any, the adoption of FAS 155 may have on our financial position and results of operations.

FAS 156, "Accounting for Servicing of Financial Assets, an amendment of FASB Statement No. 140."In March 2006, the
FASB issued FAS 156, "Accounting for Servicing of Financial Assets, an amendment of FASB Statement No. 140," which requires that servicing assets and servicing liabilities be recognized
at fair value, if practicable, when we enter into a servicing agreement and allows two alternatives, the amortization and fair value measurement methods, as subsequent measurement methods. This
accounting standard is effective for all new transactions occurring as of the beginning of fiscal years beginning after September 15, 2006. We have not yet determined the effect, if any, the
adoption of FAS 156 may have on our financial position and results of operations.

FACTORS AFFECTING FUTURE OPERATING RESULTS

Our future operating results could differ materially from the results described in this report due to the risks and uncertainties related to our business,
including those discussed below.

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Our financial results are highly dependent on sales of Cerezyme.

We generate a significant portion of our revenue from sales of Cerezyme, our enzyme-replacement product for patients with Gaucher disease. Sales of Cerezyme
totaled $239.0 million for the quarter ended March 31, 2006, representing approximately 33% of our consolidated total revenue for the quarter. Because our business is highly dependent on
Cerezyme, negative trends in revenue from this product could have a significant adverse effect on our operations and cause the value of our securities to decline substantially. We will lose revenue if
alternative treatments gain commercial acceptance, if our marketing activities are restricted, or if reimbursement is limited. In addition, the patient population with Gaucher disease is not large.
Because a significant percentage of that population already uses Cerezyme, opportunities for future sales growth are constrained. Furthermore, changes in the methods for treating patients with Gaucher
disease, including treatment protocols that combine
Cerezyme with other therapeutic products or reduce the amount of Cerezyme prescribed, could limit growth, or result in a decline, in Cerezyme sales.

If we fail to increase sales of several products and services, we will not meet our financial goals.

Over the next few years, our success will depend substantially on our ability to increase revenue from many different products and services. The products and
services include Cerezyme, Fabrazyme, Aldurazyme, Myozyme, Renagel, Hectorol, Synvisc, Thymoglobulin, Thyrogen, Clolar, Campath and diagnostic testing services. Our ability to increase sales will
depend on a number of factors, including:



Part
of our growth strategy involves conducting additional clinical trials to support approval of expanded uses of some of our products and pursuing marketing approval for our products
in new jurisdictions. For example, we are seeking marketing approval for the use of Synvisc to treat pain associated with osteoarthritis of the hip in the United States and the shoulder and ankle in
the European Union. The success of this component of our growth strategy will depend on the content and timing of our submissions to regulatory authorities and whether and when those authorities
determine to grant approvals.

Because
the healthcare industry is extremely competitive and regulatory requirements are rigorous, we spend substantial funds marketing our products and attempting to expand approved
uses for them. These expenditures depress near-term profitability, with no assurance that the expenditures will generate future profits that justify the expenditures.

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Our future success will depend on our ability to effectively develop and market our products and services against those of our competitors.

The human healthcare products and services industry is extremely competitive. Other organizations, including pharmaceutical, biotechnology, device and diagnostic
testing companies, have developed and are developing products and services to compete with our products, services, and product candidates. If healthcare providers, patients or payors prefer these
competitive products or services or these competitive products or services have superior safety, efficacy, pricing or reimbursement characteristics, we will have difficulty maintaining or increasing
the sales of our products and services.

UCB
S.A. has developed Zavesca®, a small molecule drug for the treatment of Gaucher disease, the disease addressed by Cerezyme. Zavesca has been approved in the United
States, European Union and Israel as an oral therapy for use in patients with mild to moderate Type 1 Gaucher disease for whom enzyme replacement is unsuitable. In addition, Shire Pharmaceuticals
Group plc, or Shire, is conducting a phase 1/2 clinical trial for its gene-activated glucocerebrosidase program, also to treat Gaucher disease. We are also aware of other development
efforts aimed at treating Gaucher disease.

Renagel
competes with two other products approved in the United States for the control of elevated phosphorus levels in patients with chronic kidney failure and on hemodialysis. Nabi
Biopharmaceuticals markets PhosLo®, a calcium-based phosphate binder, and Shire markets Fosrenol®, a non-calcium based phosphate binder. Nabi Biopharmaceuticals has
filed for marketing approval of PhosLo in the European Union. Shire has received marketing approval for Fosrenol in certain European countries and has filed for approval in additional European
countries and Canada. Renagel also competes with over-the-counter calcium carbonate products such as TUMS®.

Both
the oral and the intravenous formulations of Hectorol face competition. Abbott Laboratories markets intravenous Calcijex® and intravenous Zemplar® in the
United States and Europe. More recently it has begun marketing an oral formulation of Zemplar in the United States. Hectorol faces competition from several other vitamin D hormone therapies used to
treat hyperparathyroidism and hyperproliferative diseases as well.

Outside
the United States, Shire is marketing Replagal, a competitive enzyme replacement therapy for Fabry disease which is the disease addressed by Fabrazyme. In addition,
while Fabrazyme has received orphan drug designation, which provides us with seven years of market exclusivity for the product in the United States, other companies may seek to overcome our market
exclusivity and, if successful, compete with Fabrazyme in the United States.

Several
companies market products that, like Thymoglobulin and Lymphoglobuline, are used for the prevention and treatment of acute rejection in renal transplant. These products include
Novartis' Simulect®, Pfizer Inc.'s ATGAM®, Ortho Biotech's Orthoclone OKT®3, Fresenius Biotech GmbH's ATG-Fresenius S® and the Roche
Group's Zenapax®. Competition in the acute transplant rejection market largely is driven by product efficacy due to the potential loss of transplanted organs as the result of an acute
organ rejection episode.

Current
competition for Synvisc includes Supartz, a product manufactured by Seikagaku Kogyo that is sold in the United States by Smith & Nephew Orthopaedics and in Japan by Kaken
Pharmaceutical Co. under the name Artz®; Hyalgan®, produced by Fidia Farmaceutici S.p.A. and marketed in the United States by Sanofi-Aventis; Orthovisc®, produced
by Anika Therapeutics, Inc., marketed in the United States by Johnson & Johnson and marketed outside the United States through distributors; Euflexxa, a product manufactured
and sold by Ferring Pharmaceuticals and marketed in the United States and Europe; and Durolane®, manufactured and distributed outside the United States by Q-Med AB. Durolane
and Euflexxa, the most recently approved products in Europe and the United States, respectively, are produced by bacterial fermentation, as opposed to Synvisc, which is avian-

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sourced.
In addition, the treatment protocol for Durolane is a single injection, as compared to Synvisc's three injection regimen (although it offers a shorter duration of pain relief). Production via
bacterial fermentation and treatment with a reduced number of injections may represent competitive advantages for these products. We are aware of various viscosupplementation products on the market or
in development, but are unaware of any products that have physical properties of viscosity, elasticity or molecular weight comparable to those of Synvisc. Furthermore, several companies market
products that are not viscosupplementation products but which are designed to relieve the pain associated with osteoarthritis. Synvisc will have difficulty competing with any of these products to the
extent the competitive products are considered more efficacious, less burdensome to administer or more cost-effective.

The
examples above are illustrative. Almost all of our products and services face competition. Furthermore, the field of biotechnology is characterized by significant and rapid
technological change. Discoveries by others may make our products or services obsolete. For example, competitors may develop approaches to treating lysosomal storage disorders (LSDs) that are more
effective, convenient or less expensive than our products and product candidates. Because a significant portion of our revenue is derived from products that address this class of diseases and a
substantial portion of our expenditures is devoted to developing new therapies for this class of diseases, such a development would have a material negative impact on our operations. Furthermore, we
are committed to expanding
our oncology portfolio. Many pharmaceutical and biotechnology companies are pursuing programs in this area, and these organizations may develop approaches that are superior to ours.

If we fail to obtain adequate levels of reimbursement for our products from third party payors, the commercial potential of our products will be significantly limited.

A substantial portion of our domestic and international revenue comes from payments by third party payors, including government health administration authorities
and private health insurers. Governments and other third party payors may not provide adequate insurance coverage or reimbursement for our products and services, which could impair our financial
results.

Third
party payors are increasingly scrutinizing pharmaceutical budgets and healthcare expenses and are attempting to contain healthcare costs by:



Attempts
by third party payors to reduce costs in any of these ways could decrease demand for our products. In addition, in certain countries, including countries in the European Union
and Canada, the coverage of prescription drugs, the pricing, and the level of reimbursement are subject to governmental control. Therefore, we may be unable to negotiate coverage, pricing and/or
reimbursement on terms that are favorable to us. Government health administration authorities may also rely on analyses of the cost-effectiveness of certain therapeutic products in
determining whether to provide reimbursement for such products. Our ability to obtain satisfactory pricing and reimbursement may depend in part on

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whether
our products, the cost of some of which is high in comparison to other therapeutic products, are viewed as cost-effective.

Furthermore,
governmental regulatory bodies, such as the Centers for Medicare and Medicaid Services (CMS), may from time-to-time also attempt to make unilateral
changes to reimbursement rates for our products and services. These changes could reduce our revenues by causing healthcare providers to be less willing to use our products and services. Although we
actively seek to assure that any initiatives that are undertaken by regulatory agencies involving reimbursement do not have an adverse impact on us, we may not always be successful in these efforts.
For example, in November 2005, CMS announced it intended to implement a change to the billing code for viscosupplement products that would have provided Medicare reimbursement for Synvisc at a
rate that was lower than the price healthcare providers were paying for the product. If the CMS billing code change had been implemented, our Synvisc revenues would have been adversely affected
because healthcare providers would have been less willing to use Synvisc. Although CMS decided not to implement this change for 2006, the proposal is under review for 2007. We cannot determine whether
there will be similar or different changes to reimbursement codes implemented in the future.

The development of new biotechnology products involves a lengthy and complex process, and we may be unable to commercialize any of the products we are currently developing.

We have multiple products under development and devote considerable resources to research and development, including clinical trials. For example, we are spending
considerable resources attempting to develop new treatments for Gaucher disease.

Before
we can commercialize our development-stage product candidates, we will need to:



This
process involves a high degree of risk and takes many years. Our product development efforts with respect to a product candidate may fail for many reasons, including:



Few
research and development projects result in commercial products, and success in preclinical studies or early clinical trials often is not replicated in later studies. We may decide
to abandon development of a product or service candidate at any time or we may be required to expend considerable resources repeating clinical trials or conducting additional trials, either of which
would increase costs of development and delay any revenue from those product candidates.

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Our
efforts to expand the approved indications for our products and to gain marketing approval in new jurisdictions also may fail. These expansion efforts are subject to many of the
risks associated with completely new products, and, accordingly, we may fail to recoup the investments we make pursuing these expansions.

Guidelines and recommendations published by various organizations can reduce the use of our products.

Professional societies, practice management groups, private health/science foundations, and organizations involved in various diseases may publish guidelines or
recommendations to the health care and patient communities from time to time. Recommendations of government agencies or these other groups/organizations may relate to such matters as usage, dosage,
route of administration, cost-effectiveness, and use of related therapies. Organizations like these have in the past made recommendations about our products and products of our
competitors. Recommendations or guidelines that are followed by patients and healthcare providers could result in decreased use of our products. In addition, the perception by the investment community
or shareholders that recommendations or guidelines will result in decreased use of our products could adversely affect prevailing market price for our common stock. Our success also depends on our
ability to educate patients and healthcare providers about our products and their uses. If these education efforts are not effective, then we may not be able to increase the sales of our existing
products or successfully introduce new products to the market.

We may encounter substantial difficulties managing our growth.

Several risks are inherent to our plans to grow our business. Achieving our goals will require substantial investments in research and development, sales and
marketing, and facilities. For example, we have spent considerable resources building out and seeking regulatory approvals for our manufacturing plants. We cannot assure you that these facilities will
prove sufficient to meet demand for our products or that we will not have excess capacity at these facilities. In addition, building our facilities is expensive, and our ability to recover these costs
will depend on increased revenue from the products produced at the facilities.

We
produce relatively small amounts of material for research and development activities and pre-clinical trials. Even if a product candidate receives all necessary approvals
for commercialization, we may not be able to successfully scale up production of the product material at a reasonable cost or at all.

If
we are able to grow sales of our products, we may have difficulty managing inventory levels. Marketing new therapies is a complicated process, and gauging future demand is difficult.
With Renagel, for example, we have encountered problems in the past managing inventory levels at wholesalers. Comparable problems may arise with our other products, particularly during market
introduction.

Growth
in our business may also contribute to fluctuations in our operating results, which may cause the price of our securities to decline. Our revenue may fluctuate due to many
factors, including changes in:



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We
may also experience fluctuations in our quarterly results due to price changes and sales incentives. For example, purchasers of our products, particularly wholesalers, may increase
purchase orders in anticipation of a price increase and reduce order levels following the price increase. We occasionally offer sales incentives and promotional discounts on some of our products and
services that could have a similar impact. In addition, some of our products, including Synvisc, are subject to seasonal fluctuation in demand.

Our
operating results and financial position also may be impacted when we attempt to grow through business combination transactions. We may encounter problems assimilating operations
acquired in these transactions. Business combination transactions often entail the assumption of unknown liabilities, the loss of key employees, and the diversion of management attention. Furthermore,
in any business combination, including our acquisitions of the Physician Services and Analytical Services business units of IMPATH, ILEX Oncology and Bone Care, there is a substantial risk that we
will fail to realize the benefits we anticipate when we decide to undertake the transaction. We have in the past taken significant charges for impairment of goodwill and for impaired assets acquired
in business combination transactions. We may be required to take similar charges in the future.

Manufacturing problems may cause product launch delays, inventory shortages, recalls and unanticipated costs.

In order to generate revenue from our approved products, we must be able to produce sufficient quantities of the products. Many of our products are difficult to
manufacture. Our products that are biologics, for example, require product characterization steps that are more onerous than those required for most chemical pharmaceuticals. Accordingly, we employ
multiple steps to attempt to control the manufacturing processes. Minor deviations in these manufacturing processes could result in unacceptable changes in the products that result in lot failures,
product recalls, or product liability.

Certain
of the raw materials required in the commercial manufacturing and the formulation of our products are derived from biological sources, including mammalian sources and human
plasma. Such raw materials may be subject to contamination or recall. Also, some countries in which we market our products may restrict the use of certain biologically derived substances in the
manufacture of drugs. A material shortage, contamination, recall, or restriction of the use of certain biologically derived substances in the manufacture of our products could adversely impact or
disrupt our commercial
manufacturing of our products or could result in a mandated withdrawal of our products from the market. This too, in turn, could adversely affect our ability to satisfy demand for our products, which
could materially and adversely affect our operating results.

In
addition, we may only be able to produce certain of our products at a very limited number of facilities and, in some cases, we rely on third parties to formulate and manufacture our
products. For example, we manufacture all of our Cerezyme and a portion of our Fabrazyme products at our facility in Allston, Massachusetts. A number of factors could cause production interruptions at
our facilities or the facilities of our third party providers, including equipment malfunctions, labor problems, natural disasters, power outages, terrorist activities, or disruptions in the
operations of our suppliers.

Manufacturing
is also subject to extensive government regulation. Regulatory authorities must approve the facilities in which human healthcare products are produced. Any third party we
use to manufacture, fill-finish or package our products to be sold must also be licensed by the applicable regulatory authorities. As a result, alternative third party providers may not be
readily available on a timely basis. In addition, facilities are subject to ongoing inspections and minor changes in manufacturing processes may require additional regulatory approvals, either of
which could cause us to incur significant additional costs and lose revenue.

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We rely on third parties to provide us with materials and services in connection with the manufacture of our products.

Certain materials necessary for commercial production of our products, including specialty chemicals and components necessary for manufacture,
fill-finish and packaging, are provided by unaffiliated third-party suppliers. In some cases, such materials are specifically cited in our marketing application with regulatory authorities
so that they must be obtained from that specific source unless and until the applicable authority approved another supplier. In addition, there may only be one available source for a particular
chemical or component. For example, we acquire polyalylamine (PAA), used in the manufacture of Renagel and WelChol, from Cambrex Charles City, Inc., the only source for this material currently
qualified in our FDA drug applications for these products. Our suppliers also may be subject to FDA regulations or the regulations of other governmental agencies outside the United States regarding
manufacturing practices. We may be unable to manufacture our products in a timely manner or at all if these third-party suppliers were to cease or interrupt production or otherwise fail to supply
these materials or products to us for any reason, including due to regulatory requirements or actions, adverse financial developments at or affecting the supplier, or labor shortages or disputes.

We
also source some of our manufacturing, fill-finish, packaging and distribution operations to third-party contractors. The manufacture of products, fill-finish,
packaging
and distribution of our products requires successful coordination among these third-party providers and Genzyme. Our inability to coordinate these efforts, the lack of capacity available at a
third-party contractor or any other problems with the operations of these third-party contractors could require us to delay shipment of saleable products, recall products previously shipped or could
impair our ability to supply products at all. This could increase our costs, cause us to lose revenue or market share and damage our reputation.

If our strategic alliances are unsuccessful, our operating results will be negatively impacted.

Several of our strategic initiatives involve alliances with other biotechnology and pharmaceutical companies, including a joint venture with BioMarin
Pharmaceutical Inc. with respect to Aldurazyme, Schering AG with respect to Campath, and Bioenvision with respect to Clolar. The success of this and similar arrangements is largely dependent on
technology and other intellectual property contributed by our strategic partners or the resources, efforts, and skills of our partners. Disputes and difficulties in such relationships are common,
often due to conflicting priorities or conflicts of interest. Merger and acquisition activity may exacerbate these conflicts. The benefits of these alliances are reduced or eliminated when strategic
partners:



Furthermore,
payments we make under these arrangements may exacerbate fluctuations in our financial results. In addition, under some of our strategic alliances, we make milestone
payments well in advance of commercialization of products with no assurance that we will ever recoup these payments. We also may make equity investments in our strategic partners, as we did with
RenaMed in June 2005. Our strategic equity investments are subject to market fluctuations, access to capital and other business events, such as initial public offerings, the completion of
clinical trials and regulatory approvals, which
can impact the value of these investments. As a result, if any of our strategic equity investments decline in value and remain below cost for an extended duration, we may incur financial statement
charges related to the decline in value of that investment.

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Government regulation imposes significant costs and restrictions on the development and commercialization of our products and services.

Our success will depend on our ability to satisfy regulatory requirements. We may not receive required regulatory approvals on a timely basis or at all.
Government agencies heavily regulate the production and sale of healthcare products and the provision of healthcare services. In particular, the FDA and comparable agencies in foreign jurisdictions
must approve human therapeutic and diagnostic products before they are marketed, as well as the facilities in which they are made. This approval process can involve lengthy and detailed laboratory and
clinical testing, sampling activities and other costly and time-consuming procedures. Several biotechnology companies have failed to obtain regulatory approvals because regulatory agencies
were not satisfied with the structure or conduct of clinical trials. Similar problems could delay or prevent us from obtaining approvals. Furthermore, regulatory authorities, including the FDA, may
not agree with our interpretations of our clinical trial data, which could delay, limit or prevent regulatory approvals.

Therapies
that have received regulatory approval for commercial sale may continue to face regulatory difficulties. If we fail to comply with applicable regulatory requirements,
regulatory authorities could take actions against us, including:



Furthermore,
the FDA and comparable foreign regulatory agencies may require post-marketing clinical trials or patient outcome studies. We have agreed with the FDA, for
example, to a number of post-marketing commitments as a condition to U.S. marketing approval for Fabrazyme, Aldurazyme and Myozyme. In addition, regulatory agencies subject a marketed
therapy, its manufacturer and the manufacturer's facilities to continual review and periodic inspections. The discovery of previously unknown problems with a therapy or the facility used to produce
the therapy could prompt a regulatory authority to impose restrictions on us, or could cause us to voluntarily adopt such restrictions, including withdrawal of one or more of our products or services
from the market.

We
believe some of our products are prescribed by physicians for uses not approved by the FDA or comparable regulatory agencies outside the United States. Although physicians may
lawfully prescribe our products for off-label uses, any promotion by us of off-label uses would be unlawful. Some of our practices intended to make physicians aware of
off-label uses of our products without engaging in off-label promotion could nonetheless be construed as off-label promotion. Although we have policies and
procedures in place designed to help assure ongoing compliance with regulatory requirements regarding off-label promotion, some non-compliant actions may nonetheless occur.
Regulatory authorities could take enforcement action against us if they believe we are promoting, or have promoted, our products for off-label use.

We may incur substantial costs as a result of litigation or other proceedings.

A third party may sue us or one of our strategic collaborators for infringing the third party's patent or other intellectual property rights. Likewise, we or one
of our strategic collaborators may sue to enforce intellectual property rights or to determine the scope and validity of third party proprietary

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rights.
If we do not prevail in this type of litigation, we or our strategic collaborators may be required to:



We
are also currently involved in litigation matters and investigations that do not involve intellectual property claims and may be subject to additional actions in the future. For
example, we are currently defending several lawsuits brought in connection with the elimination of our tracking stock in June 2003, some of which claim considerable damages. Also, the federal
government, state governments and private payors are investigating and have begun to file actions against numerous pharmaceutical and biotechnology companies, including Genzyme, alleging that the
companies have overstated prices in order to inflate reimbursement rates. Domestic and international enforcement authorities also have instituted actions under healthcare "fraud and abuse" laws,
including anti-kickback and false claims statutes. Moreover, individuals who use our products or services, including our diagnostic products and genetic testing services, sometimes bring
product and professional liability claims against us or our subsidiaries.

We
may also become subject to investigations by government authorities in connection with our business activities. For example, we are currently cooperating with an investigation of Bone
Care by the United States Attorney for the Eastern District of New York which was initiated in October 2004, when Bone Care received a subpoena requiring it to provide a wide range of documents
related to numerous aspects of its business.

We
have only limited amounts of insurance, which may not provide coverage to offset a negative judgment or a settlement payment. We may be unable to obtain additional insurance in the
future, or we may be unable to do so on acceptable terms. Any additional insurance we do obtain may not provide adequate coverage against any asserted claims.

Regardless
of merit or eventual outcome, investigations and litigations can result in:



Our international sales and operations are subject to the economic, political, legal and business environments of the countries in which we do business, and our failure to
operate successfully or adapt to changes in these environments could cause our international sales and operations to be limited or disrupted.

Our international operations accounted for approximately 45% of our consolidated product and service revenues for the three months ended March 31, 2006. We
expect that international product and service sales will continue to account for a significant percentage of our revenues for the foreseeable future. In addition, we have direct investments in a
number of subsidiaries outside of the United States, primarily in the European Union, Latin America and Japan. Our international sales and operations

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could
be limited or disrupted, and the value of our direct investments may be diminished, by any of the following:



Our
operations and marketing practices are also subject to regulation and scrutiny by the governments of the other countries in which we operate. In addition, the Foreign Corrupt
Practices Act prohibits U.S. companies and their representatives from offering, promising, authorizing or making payments to foreign officials for the purpose of obtaining or retaining business
abroad. Failure to comply with domestic or foreign laws could result in various adverse consequences, including possible delay in approval or refusal to approve a product, recalls, seizures,
withdrawal of an approved product from the market, and/or the imposition of civil or criminal sanctions.

A
significant portion of our business is conducted in currencies other than our reporting currency, the U.S. dollar. We recognize foreign currency gains or losses arising from our
operations in the period in which we incur those gains or losses. As a result, currency fluctuations among the U.S. dollar and the currencies in which we do business have caused foreign currency
transaction gains and losses in the past and will likely do so in the future. Because of the number of currencies involved, the variability of currency exposures and the potential volatility of
currency exchange rates, we may suffer significant foreign currency transaction losses in the future due to the effect of exchange rate fluctuations.

We may fail to adequately protect our proprietary technology, which would allow competitors or others to take advantage of our research and development efforts.

Our long-term success largely depends on our ability to market technologically competitive products. If we fail to obtain or maintain adequate
intellectual property protection in the United States or abroad, we may not be able to prevent third parties from using our proprietary technologies. Our currently pending or future patent
applications may not result in issued patents. Patent applications are confidential for 18 months following their filing, and because third parties may have filed patent applications for
technology covered by our pending patent applications without us being aware of those applications, our patent applications may not have priority over patent applications of others. In addition, our
issued patents may not contain claims sufficiently broad to protect us against third parties with similar technologies or products, or provide us with any competitive advantage. If a third party
initiates litigation regarding our patents, our collaborators' patents, or those patents for which we have license rights, and is successful, a court could declare our patents invalid or unenforceable
or limit the

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scope
of coverage of those patents. Governmental patent offices and courts have not consistently treated the breadth of claims allowed in biotechnology patents. If patent offices or the courts begin
to allow or interpret claims more broadly, the incidence and cost of patent interference proceedings and the risk of infringement litigation will likely increase. On the other hand, if patent offices
or the courts begin to allow or interpret claims more narrowly, the value of our proprietary rights may be reduced. Any changes in, or unexpected interpretations of, the patent laws may adversely
affect our ability to enforce our patent position.

We
also rely upon trade secrets, proprietary know-how, and continuing technological innovation to remain competitive. We attempt to protect this information with security
measures, including the use of confidentiality agreements with employees, consultants, and corporate collaborators. These individuals may breach these agreements and any remedies available to us may
be insufficient to compensate for our damages. Furthermore, our trade secrets, know-how and other technology may otherwise become known or be independently discovered by our competitors.

We may be required to license technology from competitors or others in order to develop and commercialize some of our products and services, and it is uncertain whether these
licenses would be available.

Third party patents may cover some of the products or services that we or our strategic partners are developing or producing. A patent is entitled to a
presumption of validity, and, accordingly, we face significant hurdles in any challenge to a patent. In addition, even if we are successful in challenging the validity of a patent, the challenge
itself may be expensive and require significant management attention.

To
the extent valid third party patent rights cover our products or services, we or our strategic collaborators would be required to seek licenses from the holders of these patents in
order to manufacture, use, or sell these products and services, and payments under them would reduce our profits from these products and services. We may not be able to obtain these licenses on
acceptable terms, or at all. If we fail to obtain a required license or are unable to alter the design of our technology to fall outside the scope of a third party patent, we may be unable to market
some of our products and services, which would limit our profitability.

Importation of products from Canada and other countries into the United States may lower the prices we receive for our products.

In the United States and abroad, many of our products are subject to competition from lower-priced versions of our products and competing products from other
countries where government price controls or other market dynamics result in lower prices for such products. Our products that require a prescription in the United States may be available to consumers
in markets such as Canada, Mexico, Taiwan and the Middle East without a prescription, which may cause consumers to further seek out these products in these lower priced markets. The ability of
patients and other customers to obtain these lower priced imports has grown significantly as a result of the Internet, an expansion of pharmacies in Canada and elsewhere that target American
purchasers, the increase in U.S.-based businesses affiliated with Canadian pharmacies marketing to American purchasers, and other factors. Most of these foreign imports are illegal under current
United States law. However, the volume of imports continues to rise due to the limited enforcement resources of the FDA and the United States Customs Service, and there is increased political pressure
to permit such imports as a mechanism for expanding access to lower priced medicines.

The
importation of lower-priced versions of our products into the United States and other markets adversely affects our profitability. This impact could become more significant in the
future.

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Legislative or regulatory changes may adversely impact our business.

The United States government and other governments have shown significant interest in pursuing healthcare reform. Any government-adopted reform measures could
adversely impact:



New
laws, regulations and judicial decisions, or new interpretations of existing laws, regulations and decisions, that relate to healthcare availability, methods of delivery or payment
for products and services, or sales, marketing or pricing may cause our revenue to decline, and we may need to revise our research and development programs.

We may require significant additional financing, which may not be available to us on favorable terms, if at all.

As of March 31, 2006, we had $1.2 billion in cash, cash equivalents and short- and long-term investments, excluding investments in
equity securities.

We
intend to use substantial portions of our available cash for:



We
may further reduce available cash reserves to pay principal and interest on outstanding debt, including our $690.0 million in principal of 1.25% convertible senior notes.

To
satisfy our cash requirements, we may have to obtain additional financing. We may be unable to obtain any additional financing or extend any existing financing arrangements at all or
on terms that we or our investors consider favorable.

Our level of indebtedness may harm our financial condition and results of operations.

At March 31, 2006, we had $700.0 million of outstanding indebtedness, excluding capital leases. We may incur additional indebtedness in the future.
Our level of indebtedness will have several important effects on our future operations, including:



Our
ability to make payments and interest on our indebtedness depends upon our future operating and financial performance.

ITEM 3. QUANTITATIVE AND QUALITATIVE ANALYSIS OF MARKET RISK

Market Risk

We are exposed to potential loss from exposure to market risks represented principally by changes in equity prices, interest rates and foreign exchange rates. At
March 31, 2006, we held various derivative contracts in the form of foreign exchange forward contracts. The derivatives contain no

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leverage
or option features. We also held a number of other financial instruments, including investments in marketable securities, and have issued various debt securities.

Equity Price Risk

We hold investments in a limited number of U.S. and European equity securities. We estimated the potential loss in fair value due to a 10% decrease in equity
prices of each security held at March 31, 2006 to be $10.5 million, as compared to $11.6 million at December 31, 2005. This estimate assumes no change in foreign exchange
rates from quarter-end spot rates and excludes any potential risk associated with securities that do not have readily determinable market value.

Interest Rate Risk

We are exposed to potential loss due to changes in interest rates. The principal interest rate exposure is to changes in U.S. interest rates. Instruments with
interest rate risk include short- and long-term investments in fixed income securities. Other exposures to interest rate risk include fixed rate convertible debt and fixed rate debt. To
estimate the potential loss due to changes in interest rates, we performed a sensitivity analysis using the instantaneous adverse change in interest rates of 100 basis points across the yield curve.

We
used the following assumptions in preparing the sensitivity analysis for our convertible bonds:



On
this basis, we estimate the potential loss in fair value that would result from a hypothetical 1% (100 basis point) increase in interest rates to be $4.2 million as of
March 31, 2006, as compared to $5.9 million as of December 31, 2005. The decrease is primarily due to decreases in interest rate sensitivity on our fixed income investment
portfolio, our $690.0 million in principal of 1.25% convertible notes, and the capital lease for our corporate headquarters in Cambridge, Massachusetts, which has a remaining principal balance
of $120.2 million at March 31, 2006.

Foreign Exchange Risk

As a result of our worldwide operations, we may face exposure to adverse movements in foreign currency exchange rates, primarily to the Euro, British pound and
Japanese yen. These exposures are reflected in market risk sensitive instruments, including foreign currency receivables and payables, foreign exchange forward contracts and foreign equity holdings.

As
of March 31, 2006, we estimate the potential loss in fair value of our foreign currency contracts that would result from a hypothetical 10% adverse change in exchange rates to
be $3.0 million, as compared to $2.9 million as of December 31, 2005.

We
incorporate by reference our disclosure related to market risk which is set forth under the heading "Management's Discussion and Analysis of Genzyme Corporation and Subsidiaries'
Financial Condition and Results of OperationsMarket Risk," "Interest Rate Risk," "Foreign Exchange Risk" and "Equity Price Risk" in
Exhibit 13.1 to our 2005 Form 10-K.

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ITEM 4. CONTROLS AND PROCEDURES

At the direction of our Chief Executive Officer and Chief Financial Officer, we evaluated our disclosure controls and procedures and internal control over
financial reporting and concluded that (1) our disclosure controls and procedures were effective as of March 31, 2006, and (2) no change in internal control over financial
reporting occurred during the quarter ended March 31, 2006 that has materially affected, or is reasonably likely to materially affect, such internal control over financial reporting.

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PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

Legal Proceedings

We periodically become subject to legal proceedings and claims arising in connection with our business.

Four
lawsuits have been filed against us regarding the exchange of all of the outstanding shares of Biosurgery Stock for shares of Genzyme Stock in connection with the elimination of our
tracking stocks in July 2003. Each of the lawsuits is a purported class action on behalf of holders of Biosurgery Stock. The first case, filed in Massachusetts Superior Court in
May 2003, alleged a breach of the implied covenant of good faith and fair dealing in our charter and a breach of our board of directors' fiduciary
duties. The plaintiff in this case sought an injunction to adjust the exchange ratio for the tracking stock exchange. The Court dismissed the complaint in its entirety in November 2003. Upon
appeal, the Massachusetts Appeals Court upheld the dismissal by the Superior Court of the fiduciary duty claim, but reversed the earlier decision to dismiss the implied covenant claim. In
April 2006, we filed with the Massachusetts Supreme Judicial Court (SJC) a petition for further appellate review of the Appeals Court decision reversing the dismissal of the implied covenant
claim. We are awaiting the SJC's decision. Two substantially similar cases were filed in Massachusetts Superior Court in August and October 2003. These cases were consolidated in
January 2004, and in July 2004, the consolidated case was stayed pending disposition of a fourth case, which was filed in the U.S. District Court for the Southern District of New York in
June 2003. The complaint initially alleged violations of federal securities laws, common law fraud, and a breach of the merger agreement with Biomatrix, in addition to the state law claims
contained in the other cases. The plaintiffs initially sought an adjustment to the exchange ratio, the rescission of the acquisition of Biomatrix, and unspecified compensatory damages. In
December 2005, the plaintiffs in this case filed an amended complaint in which they dropped all of the claims alleged in the initial complaint relating to the initial issuance of Biosurgery
Stock and the acquisition of Biomatrix, and narrowed the putative class to include only those individuals who held Biosurgery Stock on May 8, 2003. We have filed a motion to dismiss the amended
complaint and to oppose the class certification, and are awaiting a decision from the Court. Discovery in this case has been put on hold pending resolution of these motions. We believe each of these
cases is without merit and continue to defend against them vigorously.

On
March 27, 2003, the OFT, in the United Kingdom issued a decision against our wholly-owned subsidiary, Genzyme Limited, finding that Genzyme Limited held a dominant position and
abused that dominant position with no objective justification by pricing Cerezyme in a way that excludes other delivery/homecare service providers from the market for the supply of home delivery and
homecare services to Gaucher patients being treated with Cerezyme. In conjunction with this decision, the OFT imposed a fine on Genzyme Limited and required modification to its list price for Cerezyme
in the United Kingdom. Genzyme Limited appealed this decision to the Competition Appeal Tribunal. On May 6, 2003, the Tribunal issued an order that stayed the OFT's decision, but required
Genzyme Limited to provide a homecare distributor a discount of 3% per unit during the appeal process. The Tribunal issued its judgment on Genzyme Limited's appeal on March 11, 2004, rejecting
portions of the OFT's decision and upholding others. The Tribunal found that the list price of Cerezyme should not be reduced, but that Genzyme Limited must negotiate a price for Cerezyme that will
allow homecare distributors an appropriate margin. The Tribunal also reduced the fine imposed by the OFT for violation of U.K. competition laws. In response to the Tribunal's decision, we recorded an
initial liability of approximately $11 million in our 2003 financial statements and additional liabilities totaling approximately $1 million during 2004 and 2005, of which approximately
$6 million were paid in 2005. As of December 31, 2005 and March 31, 2006, accrued expenses in our consolidated balance sheets includes the remaining $6 million of
liabilities recorded in connection with the Tribunal's decision.

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Genzyme
Limited and the OFT were unable to negotiate a price for Cerezyme for homecare distributors and, as a result, on September 29, 2005, the Tribunal issued a ruling establishing the
discount to be provided by Genzyme Limited to homecare distributors at 7.2%, which approximates the figure used to calculate the initial liability of approximately $11 million we recorded in
2003, and the additional liabilities totaling approximately $1 million we recorded in 2004 and 2005. Genzyme Limited has decided not to appeal this decision. Arising out of the OFT decision, on
April 5, 2006, Genzyme Limited received a damage claim from Genzyme Limited's former distributor, Healthcare at Home. Genzyme Limited and Healthcare at Home are in negotiations to arrive at a
mutually agreed upon settlement of this damage claim. We do not expect that settlement of this damage claim will have a material impact on our financial condition or results of operations.

We
are not able to predict the outcome of the pending legal proceedings listed here, or other legal proceedings, or estimate the amount or range of any reasonably possible loss we might
incur if we do not prevail in the final, non-appealable determinations of such matters. Therefore, except for the liabilities recorded in connection with the Tribunal's decision regarding
Cerezyme pricing in the United Kingdom, we have no current accruals for these potential contingencies. We cannot provide you with assurance that the legal proceedings listed here, or other legal
proceedings, will not have a material adverse impact on our financial condition or results of operations.

ITEM 1A. RISK FACTORS

We incorporate by reference our disclosure related to risk factors which is set forth under the heading "Management's Discussion and Analysis of Genzyme
Corporation and Subsidiaries' Financial Condition
and Results of OperationsFactors Affecting Future Operating Results" in Part I., Item 2. of this Quarterly Report on Form 10-Q.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

We did not purchase any shares of our common stock during the first quarter of our 2006 fiscal year.

ITEM 6. EXHIBITS



See
the Exhibit Index following the signature page to this report on Form 10-Q.

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GENZYME CORPORATION AND SUBSIDIARIES  FORM 10-Q, MARCH 31, 2006  SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned
thereunto duly authorized.

|                   |  | GENZYME CORPORATION
|------------------ |  | -------------------
|                   |  | By:                
|DATE: May 10, 2006 |  |                    

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GENZYME CORPORATION AND SUBSIDIARIES  FORM 10-Q, MARCH 31, 2006    EXHIBIT INDEX

|Exhibit No. |  | Description                                                                                                                
|----------- |  | ---------------------------------------------------------------------------------------------------------------------------
|31.1        |  | Certification of the Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Filed herewith.    
|31.2        |  | Certification of the Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Filed herewith.    
|32.1        |  | Certification of the Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. Furnished herewith.
|32.2        |  | Certification of the Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. Furnished herewith.

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