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                                                                   Exhibit 10.20


                               GENZYME CORPORATION

                           1997 EQUITY INCENTIVE PLAN

1. PURPOSE

     The purpose of the Genzyme Corporation 1997 Equity Incentive Plan (the
"Plan") is to attract and retain key employees and consultants of the Company
and its Affiliates, to provide an incentive for them to achieve long-range
performance goals, and to enable them to participate in the long-term growth of
the Company by granting them Awards with respect to the Company's Common Stock.
Certain capitalized terms used herein are defined in section 9 below.

2. ADMINISTRATION

         The Plan shall be administered by the Committee. The Committee shall
select the Participants to receive Awards and shall determine the terms and
conditions of the Awards. The Committee shall have authority to adopt, alter and
repeal such administrative rules, guidelines and practices governing the
operation of the Plan as it shall from time to time consider advisable, and to
interpret the provisions of the Plan. The Committee's decisions shall be final
and binding. To the extent permitted by applicable law, the Committee may
delegate to one or more executive officers of the Company the power to make
Awards to Participants and all determinations under the Plan with respect
thereto, provided that the Committee shall fix the maximum amount of such Awards
for all such Participants and a maximum for any one Participant.

3. ELIGIBILITY

     All employees and consultants of the Company or any Affiliate capable of
contributing significantly to the successful performance of the Company are
eligible to be Participants in the Plan, other than persons deemed to be
officers of directors of the Company within the meaning of the corporate
governance rules for Nasdaq National Market companies.

4. STOCK AVAILABLE FOR AWARDS

(a) AMOUNT. Subject to adjustment under subsection (b), Awards may be made under
the Plan for up to 27,100,000 shares of Genzyme General Stock, up to 6,620,342
shares of Genzyme Biosurgery Stock and up to 2,200,000 shares of Genzyme
Molecular Oncology Stock. If any Award expires or is terminated unexercised or
is forfeited or settled in a manner that results in fewer shares outstanding
than were awarded, the shares subject to such Award, to the extent of such
expiration, termination, forfeiture or decrease, shall again be available for
award under the Plan. Common Stock issued through the assumption or substitution
of outstanding grants from an acquired company shall not reduce the shares
available for Awards under the Plan. Shares issued under the Plan may consist in
whole or in part of authorized but unissued shares or treasury shares.

(b) ADJUSTMENT. In the event that the Committee determines that any stock
dividend, extraordinary cash dividend, recapitalization, reorganization, merger,
consolidation, split-up, spin-off, combination, exchange of shares or other
transaction affects the Common Stock such that an adjustment is required in
order to preserve the benefits intended to be provided by the Plan, then the
Committee shall equitably adjust any or all of (i) the number and kind of shares
in respect of which Awards may be made under the Plan, (ii) the number and kind
of shares subject to outstanding Awards and (iii) the exercise price with
respect to any of the foregoing, provided that the number of shares subject to
any Award shall always be a whole number, and if considered appropriate, the
Committee may make provision for a cash payment with respect to an outstanding
Award. Notwithstanding the foregoing, unless otherwise determined by the
Committee, no adjustment will be made for dividends of one series of Common
Stock paid on another series of Common Stock.


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5. STOCK OPTIONS

(a) GRANT OF OPTIONS. Subject to the provisions of the Plan, the Committee may
grant Options to purchase shares of Common Stock. The Committee shall determine
the number of shares subject to each Option and the exercise price therefor,
which shall not be less than 100% of the Fair Market Value of the Common Stock
as of the Pricing Date. The Plan does not provide for the granting of incentive
stock options meeting the requirements of Section 422 of the Code.

(b) TERMS AND CONDITIONS. Each Option shall be exercisable at such times and
subject to such terms and conditions as the Committee may specify in the
applicable grant or thereafter. The Committee may impose such conditions with
respect to the exercise of Options, including conditions relating to applicable
federal or state securities laws, as it considers necessary or advisable.

(c) PAYMENT. No shares shall be delivered pursuant to any exercise of an Option
until payment in full of the exercise price therefor is received by the Company.
Such payment may be made in whole or in part in cash or, to the extent permitted
by the Committee at or after the grant of the Option, by delivery of a note or
other commitment satisfactory to the Committee or shares of Common Stock owned
by the optionee, including Restricted Stock, or by retaining shares otherwise
issuable pursuant to the Option, in each case valued at their Fair Market Value
on the date of delivery or retention, or such other lawful consideration,
including a payment commitment of a financial or brokerage institution, as the
Committee may determine.

6. STOCK EQUIVALENTS

(a) GRANT OF STOCK EQUIVALENTS. Subject to the provisions of the Plan, the
Committee may grant rights to receive payment from the Company based in whole or
in part on the value of the Common Stock. The Committee shall determine at the
time of grant or thereafter whether Stock Equivalents are settled in cash,
Common Stock or other securities of the Company, Awards or other property.

(b) STOCK APPRECIATION RIGHTS. Stock Equivalents may include rights to receive
any excess in value of shares of Common Stock over the exercise price ("Stock
Appreciation Rights" or "SARs") which may be granted in tandem with an Option
(at or after the award of the Option), or alone and unrelated to an Option. SARs
in tandem with an Option shall terminate to the extent that the related Option
is exercised, and the related Option shall terminate to the extent that the
tandem SARs are exercised. The Committee shall fix the exercise price of each
SAR or specify the manner in which the price shall be determined and may define
the manner of determining the excess in value of the shares of Common Stock. An
SAR granted in tandem with an Option shall have an exercise price not less than
the exercise price of the related Option. An SAR granted alone and unrelated to
an Option may not have an exercise price less than 100% of the Fair Market Value
of the Common Stock as of the Pricing Date.

7. STOCK GRANTS

(a) GRANT OF STOCK. Subject to the provisions of the Plan, the Committee may
grant shares of Common Stock upon such terms and conditions as the Committee
determines. Stock Grants may be issued for no cash consideration, such minimum
consideration as may be required by applicable law or such other consideration
as the Committee may determine.

(b) RESTRICTED STOCK. Stock Grants may include shares subject to forfeiture
("Restricted Stock"). The Committee will determine the duration of the period
(the "Restricted Period") during which, and the conditions under which, the
shares may be forfeited to the Company and the other terms and conditions of
such Awards. Shares of Restricted Stock may not be sold, assigned, transferred,
pledged or otherwise encumbered, except as permitted by the Committee, during
the Restricted Period. Shares of Restricted Stock shall be evidenced in such
manner as the Committee may determine. Any certificates issued in respect of
shares of Restricted Stock shall be registered in the name of the Participant
and unless otherwise


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determined by the Committee, deposited by the Participant, together with a stock
power endorsed in blank, with the Company. At the expiration of the Restricted
Period, the Company shall deliver such certificates to the Participant or if the
Participant has died, to the Participant's Designated Beneficiary.

8. GENERAL PROVISIONS APPLICABLE TO AWARDS

(a) DOCUMENTATION. Each Award under the Plan shall be evidenced by a writing
delivered to the Participant specifying the terms and conditions thereof and
containing such other terms and conditions not inconsistent with the provisions
of the Plan as the Committee considers necessary or advisable to achieve the
purposes of the Plan or to comply with applicable tax and regulatory laws and
accounting principles.

(b) COMMITTEE DISCRETION. Each type of Award may be made alone, in addition to
or in relation to any other Award. The terms of each type of Award need not be
identical, and the Committee need not treat Participants uniformly. Except as
otherwise provided by the Plan or a particular Award, any determination with
respect to an Award may be made by the Committee at the time of grant or at any
time thereafter.

(c) DIVIDENDS AND CASH AWARDS. In the discretion of the Committee, any Award
under the Plan may provide the Participant with (i) dividends or dividend
equivalents payable (in cash or in the form of Awards under the Plan) currently
or deferred with or without interest and (ii) cash payments in lieu of or in
addition to an Award.

(d) TERMINATION OF EMPLOYMENT. The Committee shall determine the effect on an
Award of the disability, death, retirement or other termination of employment of
a Participant and the extent to which, and the period during which, the
Participant's legal representative, guardian or Designated Beneficiary may
receive payment of an Award or exercise rights thereunder.

(e) CHANGE IN CONTROL. In order to preserve a Participant's rights under an
Award in the event of a change in control of the Company (as defined by the
Committee), the Committee in its discretion may, at the time an Award is made or
at any time thereafter, take one or more of the following actions: (i) provide
for the acceleration of any time period relating to the exercise or payment of
the Award, (ii) provide for payment to the Participant of cash or other property
with a Fair Market Value equal to the amount that would have been received upon
the exercise or payment of the Award had the Award been exercised or paid upon
the change in control, (iii) adjust the terms of the Award in a manner
determined by the Committee to reflect the change in control, (iv) cause the
Award to be assumed, or new rights substituted therefor, by another entity, or
(v) make such other provision as the Committee may consider equitable to
Participants and in the best interests of the Company.

(f) TRANSFERABILITY. In the discretion of the Committee, any Award may be made
transferable upon such terms and conditions and to such extent as the Committee
determines. The Committee may in its discretion waive any restriction on
transferability.

(g) LOANS. The Committee may authorize the making of loans or cash payments to
Participants in connection with the grant or exercise of any Award under the
Plan, which loans may be secured by any security, including Common Stock,
underlying or related to such Award (provided that the loan shall not exceed the
Fair Market Value of the security subject to such Award), and which may be
forgiven upon such terms and conditions as the Committee may establish at the
time of such loan or at any time thereafter.

(h) WITHHOLDING TAXES. The Participant shall pay to the Company, or make
provision satisfactory to the Committee for payment of, any taxes required by
law to be withheld in respect of Awards under the Plan no later than the date of
the event creating the tax liability. The Company and its Affiliates may, to the
extent permitted by law, deduct any such tax obligations from any payment of any
kind otherwise due to the Participant. In the Committee's discretion, such tax
obligations may be paid in whole or in part in shares of Common Stock, including
shares retained from the Award creating the tax obligation, valued at their Fair
Market Value on the date of delivery.


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(i) FOREIGN NATIONALS. Awards may be made to Participants who are foreign
nationals or employed outside the United States on such terms and conditions
different from those specified in the Plan as the Committee considers necessary
or advisable to achieve the purposes of the Plan or to comply with applicable
laws.

(j) AMENDMENT OF AWARD. The Committee may amend, modify or terminate any
outstanding Award, including substituting therefor another Award of the same or
a different type, changing the date of exercise or realization, provided that
the Participant's consent to such action shall be required unless the Committee
determines that the action, taking into account any related action, would not
materially and adversely affect the Participant.

9. CERTAIN DEFINITIONS

     "Affiliate" means any business entity in which the Company owns directly or
indirectly 50% or more of the total voting power or has a significant financial
interest as determined by the Committee.

     "Award" means any Stock Option, Stock Equivalent or Stock Grant granted
under the Plan.

     "Board" means the Board of Directors of the Company.

     "Code" means the Internal Revenue Code of 1986, as amended from time to
time, or any successor law.

     "Committee" means one or more committees each comprised of not less than
two members of the Board appointed by the Board to administer the Plan or a
specified portion thereof.

     "Common Stock" or "Stock" means the Genzyme General Stock, the Genzyme
Biosurgery Stock, the Genzyme Molecular Oncology Stock and any other series of
common stock, $.01 par value, of the Company.

     "Company" means Genzyme Corporation.

     "Designated Beneficiary" means the beneficiary designated by a Participant,
in a manner determined by the Committee, to receive amounts due or exercise
rights of the Participant in the event of the Participant's death. In the
absence of an effective designation by a Participant, "Designated Beneficiary"
means the Participant's estate.

     "Fair Market Value" means, with respect to Common Stock or any other
property, the fair market value of such property as determined by the Committee
in good faith or in the manner established by the Committee from time to time.

     "Genzyme General Stock" means the Genzyme General Division Common Stock.

     "Genzyme Biosurgery Stock" means the Genzyme Biosurgery Division Common
Stock.

     "Genzyme Molecular Oncology Stock" means the Genzyme Molecular Oncology
Division Common Stock.

     "Participant" means a person selected by the Committee to receive an Award
under the Plan.

     "Pricing Date" means the date on which the Award is granted, except that
the Committee may provide that the Pricing Date for an Award granted to a new
employee or consultant shall be the date on which the recipient is hired or
engaged if the grant of the Award occurs within 90 days of the date such
employment or engagement commences.


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     "Stock Equivalent" means a right to receive payment from the Company based
in whole or in part on the value of the Common Stock awarded to a Participant
under Section 6.

     "Stock Grant" means shares of Common Stock awarded to a Participant under
Section 7.

     "Stock Option" or "Option" means an option to purchase shares of Common
Stock awarded to a Participant under Section 5.

10. MISCELLANEOUS

(a) NO RIGHT TO EMPLOYMENT. No person shall have any claim or right to be
granted an Award. Neither the Plan nor any Award hereunder shall be deemed to
give any employee the right to continued employment or to limit the right of the
Company to discharge any employee at any time.

(b) NO RIGHTS AS STOCKHOLDER. Subject to the provisions of the applicable Award,
no Participant or Designated Beneficiary shall have any rights as a stockholder
with respect to any shares of Common Stock to be distributed under the Plan
until he or she becomes the holder thereof. A Participant to whom Common Stock
is awarded shall be considered the holder of the Stock at the time of the Award
except as otherwise provided in the applicable Award.

(c) EFFECTIVE DATE. The Plan shall be effective on October 16, 1997.

(d) AMENDMENT OF PLAN. The Board may amend, suspend or terminate the Plan or any
portion thereof at any time.

(e) GOVERNING LAW. The provisions of the Plan shall be governed by and
interpreted in accordance with the laws of Massachusetts.


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