##### Table of Contents



As filed with the Securities and Exchange Commission on March 13, 2006
   UNITED STATES SECURITIES AND EXCHANGE COMMISSION
 WASHINGTON, D. C. 20549
 
 FORM 10-K
 (MARK ONE)
 þ
    
    Annual Report Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
 For the Fiscal Year Ended December 31, 2005
 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 No. 1-3305
 
 Merck & Co., Inc.
 
 Incorporated in New Jersey
    
    I.R.S. Employer
Identification No. 22-1109110
 Securities Registered pursuant to Section 12(b) of the Act:
 Name of Each ExchangeTitle of Each Class
    
    on which RegisteredCommon Stock
($0.01 par value)
    
    New York and Philadelphia Stock Exchanges
   Yes þ No o
 Yes o No þ
 Yes þ No o
 þ
  þ o o
 Yes o No þ
 Documents Incorporated by Reference:
 Document
    
    Part of Form 10-KAnnual Report to stockholders for the fiscal year
ended December 31, 2005
    
    Parts I and IIProxy Statement for the Annual Meeting of
Stockholders to be held April 25, 2006
    
    Part III




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TABLE OF CONTENTS  PART IItem 1. BusinessItem 1A. Risk FactorsItem 1B. Unresolved Staff CommentsItem 2. PropertiesItem 3. Legal ProceedingsItem 4. Submission of Matters to a Vote of Security HoldersPART IIItem 5. Market for Registrants Common Equity, Related Stockholder Matters and Issuer Purchases of Equity SecuritiesItem 6. Selected Financial DataItem 7. Managements Discussion and Analysis of Financial Condition and Results of OperationsItem 7A. Quantitative and Qualitative Disclosures About Market RiskItem 8. Financial Statements and Supplementary DataItem 9. Changes in and Disagreements with Accountants on Accounting and Financial DisclosureItem 9A. Controls and ProceduresItem 9B. Other InformationPART IIIItem 10. Directors and Executive Officers of the RegistrantItem 11. Executive CompensationItem 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder MattersItem 13. Certain Relationships and Related TransactionsItem 14. Principal Accountant Fees and ServicesPART IVItem 15. Exhibits and Financial Statement SchedulesSIGNATURESEX-12: COMPUTATION OF RATIOS OF EARNINGS TO FIXED CHARGESEX-13: PORTIONS OF 2005 ANNUAL REPORT TO STOCKHOLDERSEX-21: SUBSIDIARIES OF MERCK & CO., INC.EX-24.1: POWER OF ATTORNEYEX-24.2: CERTIFIED RESOLUTION OF BOARD OF DIRECTORSEX-31.1: CERTIFICATIONEX-31.2: CERTIFICATIONEX-32.1: CERTIFICATIONEX-32.2: CERTIFICATION    Table of Contents  
 PART I
 
 Item 1. Business.
  Overview 
    Gardasil Zostavax RotaTeq RotaTeq Gardasil Zostavax
 Januvia
  2




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##### Table of Contents



Vioxx Vioxx
 Vioxx Vioxx Vioxx
 Vioxx
 3




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##### Table of Contents



Product Sales
 1
 ($ in millions)
    
    2005
    
    
    2004
    
    
    2003Zocor
    
    $
    4,381.7
    
    
    $
    5,196.5
    
    
    $
    5,011.4Fosamax
    
    
    3,191.2
    
    
    
    3,159.7
    
    
    
    2,676.6Cozaar/Hyzaar
    
    
    3,037.2
    
    
    
    2,823.7
    
    
    
    2,486.0Singulair
    
    
    2,975.6
    
    
    
    2,622.0
    
    
    
    2,009.4Proscar
    
    
    741.4
    
    
    
    733.1
    
    
    
    605.5Primaxin
    
    
    739.6
    
    
    
    640.6
    
    
    
    628.9Vasotec/Vaseretic
    
    
    623.1
    
    
    
    719.2
    
    
    
    763.7Cosopt/Trusopt
    
    
    617.2
    
    
    
    558.8
    
    
    
    484.4Cancidas
    
    
    570.0
    
    
    
    430.0
    
    
    
    275.7Maxalt
    
    
    348.4
    
    
    
    309.9
    
    
    
    324.2Propecia
    
    
    291.9
    
    
    
    270.2
    
    
    
    239.0Vioxx
    
    
    
    
    
    
    1,489.3
    
    
    
    2,548.8Vaccines/Biologicals
    
    
    1,103.3
    
    
    
    1,036.1
    
    
    
    1,056.1Other
    
    
    3,391.3
    
    
    
    2,949.5
    
    
    
    3,376.2Total
    
    $
    22,011.9
    
    
    $
    22,938.6
    
    
    $
    22,485.9
 
 1
 Zocor Fosamax Fosamax Plus D Fosamax Cozaar Hyzaar Vasotec , Singulair Proscar Primaxin Cancidas , s Cosopt Trusopt , Maxalt , Propecia Varivax M-M-R Pneumovax Recombivax HB
 Nexium Prilosec
 Product Approvals  Singulair
 ProQuad ProQuad
 4




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##### Table of Contents



RotaTeq RotaTeq RotaTeq RotaTeq
 Voluntary
Withdrawal of Vioxx  Vioxx Vioxx
 Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx Vioxx Vioxx
 Vioxx Vioxx
 Vioxx Vioxx Vioxx.
 Vioxx, Vioxx
 Arcoxia Arcoxia Arcoxia Arcoxia Arcoxia
 5




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##### Table of Contents



Vioxx Arcoxia Arcoxia, Arcoxia Arcoxia.
 Arcoxia Arcoxia Arcoxia Arcoxia
 Acquisitions 3⁄4
  Joint Ventures 3⁄4 Zetia ( Ezetrol Vytorin Inegy Zetia Zocor,
 , Vytorin Vytorin Zocor
 Prilosec
 6




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Nexium Prilosec Nexium Prilosec
 Nexium Prilosec
 Pepcid AC Pepcid Pepcid Complete, Divestitures
 Haemophilus influenzae
  7




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##### Table of Contents



Hexavac. Hexavac Hexavac Hexavac Hexavac Hexavac Hexavac
 HBvaxPRO Procomvax
  Competition 3⁄4
  Vasotec Vaseretic , Zocor Zocor
 8




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Distribution 3⁄4
  Raw Materials 3⁄4
 Government Regulation and Investigation 3⁄4
   9




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Patents, Trademarks and Licenses 3⁄4 per se
 Cancidas, Comvax Haemophilus , Cosopt,
Cozaar, Crixivan Emend , Fosamax,
Hyzaar Invanz Maxalt ,
Primaxin, Propecia , Proscar, Recombivax HB,
 10




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##### Table of Contents



Singulair, Timoptic-XE Trusopt, Zocor Zetia Vytorin Sustiva/Stocrin Sustiva Stocrin Aggrastat Aggrastat
 Invanz Trusopt Cozaar/Hyzaar Singulair
   Zocor Zocor
 Proscar Proscar Proscar Propecia; Propecia
 Fosamax Fosamax Fosamax Fosamax Fosamax
  11




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Discontinued Operations 3⁄4
 Divestitures 3⁄4
 Aggrastat
 Vasotec, Vaseretic Vasotec I.V. Injection Vasotec Vaseretic Vasotec Vaseretic
 Research and Development
     12




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Zostavax, Zostavax Zostavax Zostavax
 Januvia, st Januvia
 Gardasil , Gardasil Gardasil
 13




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14




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##### Table of Contents



Pargluva Pargluva Pargluva Pargluva Pargluva
  Phase I
    
    Phase I
    
    Phase II
    
    Phase III
    

Under
ReviewAlzheimers Disease
    
    Diabetes
    
    Arthritis
    
    AIDS
    
    HPV and relatedMK-0752
    
    MK-0941
    
    MK-0686
    
    MK-0518
    
    cervical cancer andMK-0952
    
    MK-0893
    
    Cancer (CTCL)
    
    Atherosclerosis
    
    genital wartsArthritis
    
    MK-0533
    
    Vorinostat*
    
    MK-0524B
    
    Gardasil**MK-0822
    
    Endocrine
    
    Endocrine
    
    MK-0524AAtherosclerosis
    
    MK-0974
    
    MK-0677
    
    CINV
    
    ShinglesMK-0354*
    
    Flu Vaccine
    
    HIV Vaccine
    
    MK-0517
    
    ZostavaxMK-0859
    
    Glaucoma
    
    HPV Vaccine**
    
    DiabetesMK-0633
    
    MK-0994
    
    Hypertension
    
    MK-0431A

    
DiabetesCancer
    
    Insomnia
    
    MK-0736
    
    Insomnia
    
    JanuviaMK-0429
    
    MK-0454
    
    Obesity
    
    Gaboxadol*MK-0752
    
    Obesity
    
    MK-0364
    
    
    
    
    
    ApprovableAgensys*
    
    Nastech PYY3-36***
    
    MK-0493
    
    
    
    
    
    Arthritis/PainMK-0731
    
    Osteoporosis
    
    Osteoporosis
    
    
    
    
    
    ArcoxiaVX-680*
    
    MK-0773
    
    MK-0822MK-0646*
    
    Pain
    
    Pain
    
    
    
    
    
    2005 U.S. ApprovalsCancer Vaccine
    
    Neurogen*
    
    MK-0686
    
    
    
    
    
    OsteoporosisCardiovascular
    
    Parkinsons Disease
    
    MK-0759
    
    
    
    
    

Fosamax
Plus DMK-0448
    
    MK-0657
    
    MK-0974
    
    
    
    
    
    Pediatric VaccinePsychiatric Disease
    
    Pediatric Vaccine*
    
    
    
    
    
    ProQuadMK-0249
    
    Psychiatric DiseaseRespiratory Disease
    
    MK-0364
    
    
    
    
    
    2006 U.S. ApprovalsMK-0633
    
    Lurasidone*
    
    
    
    
    
    RotavirusS. aureusVaccine
    
    Stroke
    
    
    
    
    
    GastroenteritisONO 2506***
    
    
    
    
    
    RotaTeqUrinary IncontinenceMK-0634MK-0594
 
 *
    
    Licensed, alliance, or acquisition (pipeline)**
    
    Multiple licenses, including CSL, Ltd.***
    
    Merck is in discussions with its licensing partner regarding further plans for this
compound.  Zetia Vytorin Cozaar Hyzaar Prilosec Nexium Vasotec Vaseretic




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Aggrastat Pargluva
 Employees
      Environmental Matters
  Geographic Area and Segment Information
  16




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##### Table of Contents



Available Information
 www.merck.com
 www.merck.com/about/corporategovernance
 
 Item 1A. Risk Factors.
  The Company faces significant litigation related to Vioxx.
 Vioxx Vioxx, Vioxx. Vioxx Vioxx Vioxx Vioxx Vioxx
 17




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Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx Vioxx Vioxx Vioxx
 Vioxx
  Vioxx Vioxx
  Vioxx Vioxx
 Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 18




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Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx Vioxx
 Certain of the Companys major products are going to lose patent protection in the near future
and, when that occurs, the Company expects a significant decline in sales of those products.
  Zocor, Zocor Zocor Zocor Zocor
 Fosamax Fosamax Fosamax Fosamax
 Fosamax Fosamax Fosamax
 19




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The Companys research and development efforts may not succeed in developing commercially
successful products and the Company may not be able to acquire commercially successful products in
other ways; in consequence, the Company may not be able to replace sales of successful products
that have lost patent protection.
 Zocor Fosamax
  Zocor Fosamax
 The Companys products, including products in development, can not be marketed unless the
Company obtains and maintains regulatory approval.
   20




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The Company is dependent on its patent rights, and if its patent rights are invalidated or
circumvented, its business would be adversely affected.
    The Company faces intense competition from lower-cost generic products.
   The Company faces intense competition from new products.
  21




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Cautionary Factors that May Affect Future Results
  
    
    Significant litigation related to Vioxx.
    
    Competition from generic products as the Companys products lose patent protection.
    
    Increased brand competition in therapeutic areas important to the Companys long-term business performance.
    
    The difficulties and uncertainties inherent in new product development. The outcome of the lengthy and complex process
of new product development is inherently uncertain. A candidate can fail at any stage of the process and one or more
late-stage product candidates could fail to receive regulatory approval. New product candidates may appear promising
in development but fail to reach the market because of efficacy or safety concerns, the inability to obtain necessary
regulatory approvals, the difficulty or excessive cost to manufacture and/or the infringement of patents or
intellectual property rights of others. Furthermore, the sales of new products may prove to be disappointing and fail
to reach anticipated levels.
    
    Pricing pressures, both in the United States and abroad, including rules and practices of managed care groups, judicial
decisions and governmental laws and regulations related to Medicare, Medicaid and health care reform, pharmaceutical
reimbursement and pricing in general.
    
    Changes in government laws and regulations and the enforcement thereof affecting the Companys business.
 22




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##### Table of Contents




    
    Efficacy or safety concerns with respect to marketed products, whether or not scientifically justified, leading to
product recalls, withdrawals or declining sales.
    
    Legal factors, including product liability claims, antitrust litigation and governmental investigations, including tax
disputes, environmental concerns and patent disputes with branded and generic competitors, any of which could preclude
commercialization of products or negatively affect the profitability of existing products.
    
    Lost market opportunity resulting from delays and uncertainties in the approval process of the FDA and foreign
regulatory authorities.
    
    Increased focus on privacy issues in countries around the world, including the United States and the EU. In the United
States, federal and state governments have pursued legislative and regulatory initiatives regarding patient privacy,
including federal and recently issued state privacy regulations concerning health information, which have affected the
Companys operations.
    
    Changes in tax laws including changes related to the taxation of foreign earnings.
    
    Changes in accounting pronouncements promulgated by standard-setting or regulatory bodies, including the Financial
Accounting Standards Board and the SEC, that are adverse to the Company.
    
    Economic factors over which the Company has no control, including changes in inflation, interest rates and foreign
currency exchange rates.
  
 Item 1B. Unresolved Staff Comments.
  
 Item 2. Properties.
    23




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##### Table of Contents



Item 3. Legal Proceedings.
  Vioxx Litigation
 Product Liability Lawsuits
 Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx
 Vioxx Vioxx
 Vioxx www.Merck.com
 24




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##### Table of Contents



Vioxx
  Vioxx Vioxx Vioxx
 th Vioxx Vioxx
 Vioxx
 Other Lawsuits
 Vioxx Vioxx Vioxx
 Vioxx Vioxx Vioxx
 25




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Shareholder Lawsuits
 Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx
 Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx
 26




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Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 International Lawsuits
 Vioxx Vioxx
 Additional Lawsuits
 Vioxx Vioxx Vioxx Vioxx
 Insurance
 Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx Vioxx
 Investigations
 Vioxx Vioxx
 27




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Vioxx Vioxx Vioxx
 Vioxx
 Reserves
 Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx
 Vioxx
 Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx Vioxx L
 Commercial Litigation
   28




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Pepcid
  Governmental Proceedings
  29




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##### Table of Contents



Pepcid
   Tienam Tienam Tienam Tienam Tienam Tienam
 Vaccine Litigation
 M-M-R
  30




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M-M-R
 Patent Litigation
 Fosamax Prilosec, Nexium Propecia, Trusopt Cosopt Prilosec Nexium Prilosec Fosamax Propecia Trusopt Cosopt Prilosec Nexium
 Fosamax Fosamax Fosamax
   31




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Fosamax Fosamax
   Trusopt Cosopt Trusopt Cosopt Cosopt Trusopt Cosopt
  Nexium
 Propecia
 32




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Cozaar
 Other Litigation
     33




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Environmental
Matters
 de minimis
   
 Item 4. Submission of Matters to a Vote of Security Holders.
  34




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##### Table of Contents



Executive
Officers of the Registrant (ages as of February 1, 2006)
  May, 2005  Chief Executive Officer and PresidentJune, 2003  President, Merck Manufacturing Division  responsible for the Companys
manufacturing, information services and operational excellence organizations worldwideJanuary, 2003  Chairman, President and Chief Executive Officer, Medco Health Solutions,
Inc. (Medco Health), formerly a wholly-owned subsidiary of the CompanyJanuary, 2000  President, Medco Health
  August, 2005  President, Human Health-Asia Pacific  responsible for the Companys
prescription drug business in the Asia Pacific region, Japan, Australia, New Zealand and
the Companys joint venture relationship with Schering-PloughJanuary, 2003  President, Human Health    responsible for the Companys prescription drug
business in Japan, Latin America, Canada, Australia, New Zealand and the Companys joint
venture relationship with Schering-PloughMarch, 2001  President, The Americas and U.S. Human Health  responsible for one of the
two prescription drug divisions comprising U.S. Human Health, as well as the Companys
prescription drug business in Canada and Latin America, and the Companys joint venture
relationship with Schering-PloughJanuary, 1997  President, Human Health 
 The Americas  responsible for the Companys human health business in the United States, Canada and Latin America
  January, 1997  Vice President, Secretary (since September, 1993) and Assistant General
Counsel (since November, 1993)
  May, 2005  President, Merck Manufacturing Division  responsible for the Companys
global manufacturing, procurement, and operational excellence functionsJanuary, 2004  Senior Vice President, Global ProcurementPrior to January, 2004, Mr. Deese was Senior Vice President, Global Procurement and
Logistics (2001 to 2003) for GlaxoSmithKline plc
  August, 2002  Vice President and Treasurer  responsible for the Companys treasury and
tax functions, and for providing financial support for the Merck Manufacturing and Merck
Research Laboratories Divisions as well as Human ResourcesSeptember, 1999  Vice President and Treasurer  responsible for the Companys treasury and
tax functions and for providing financial support for the Asia Pacific Division
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December, 1999  Senior Vice President and General Counsel  responsible for legal and
public affairs functions and The Merck Company Foundation (a not-for-profit charitable
organization affiliated with the Company)
  August, 2002  Vice President, Controller  responsible for the Corporate Controllers
Group and providing financial support for the Human Health operations in the United
States, Canada, Latin America, Europe, the Middle East, Africa, Japan, and Australia/New
Zealand and the Merck Vaccine Division (MVD)November, 2000  Vice President, Controller (since February, 1999)  responsible for the
Corporate Controllers Group and providing financial support for U.S. Human Health,
Canada and Latin America (The Americas) and MVD
  January, 2003  President, Merck Research Laboratories (MRL)February, 2001  Executive Vice President, Research and Development, MRL
  August, 2005  Executive Vice President and Chief Financial Officer  responsible for the
Companys strategic planning, financial and corporate development functions, internal
auditing, corporate licensing, the Companys joint venture relationships, and Merck
Capital Ventures, LLC, a subsidiary of the CompanyJanuary, 2003  Executive Vice President, Chief Financial Officer and President, Human
Health Asia  responsible for financial and corporate development functions, internal
auditing, corporate licensing, the Companys prescription drug business in Asia North
and Asia South, the Companys joint venture relationships, and Merck Capital Ventures,
LLCFebruary, 2001  Executive Vice President and Chief Financial Officer (since April, 1990) 
responsible for financial and corporate development functions, internal auditing,
corporate licensing, the Companys joint venture relationships, and Merck Capital
Ventures, LLC
  September, 2005  Chief Medical Advisor, Vaccines and Infectious Diseases  responsible for
representing the Company in external medical, policy and government forums on matters of
infectious diseases and vaccinesMay, 1999  President, Merck Vaccines
  August, 2005  President, Merck Vaccines  global responsibilities for the vaccines business
including the Companys Sanofi-Aventis joint ventureJanuary, 2003  President, U.S. Human Health  responsible for one of the two prescription
drug divisions (hospital and specialty product franchises) comprising U.S. Human Health
(USHH), and the Managed Care Group of USHHAugust, 2001  Executive Vice President, Customer Marketing and Sales, USHHNovember, 1998  Senior Vice President, Worldwide Human Health Marketing
 36




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##### Table of Contents



January, 2006  Senior Vice President, Global Process and Services, and Chief Information
Officer (CIO)  responsible for Global Shared Services across the human resources,
finance, site services and information services function; and the enterprise business
process redesign initiativeMarch, 2003
 Senior Vice President, Information Services, and CIO 
responsible for all areas of information technology and services including application
development, technical support, voice and data communications, and computer operations
worldwidePrior to March, 2003, Mr. Scalet was Senior Vice President, Information Technology &
CIO (1997 to 2003) for International Paper Company (global forest
products, paper and packaging company)
  August, 2005  President, U.S. Human Health  responsible for the entire prescription drug
business comprising U.S. Human Health (USHH)January, 2003  President, U.S. Human Health  responsible for one of the two prescription
drug divisions (primary care product franchises) comprising USHHMarch, 2001  President, U.S. Human Health  responsible for one of the two prescription
drug divisions (hospital and specialty product franchises) comprising USHHJuly, 1998  Vice President, Hospital Marketing and Sales, USHH
  January, 2001  Vice President, Public Affairs
  August, 2005  President, Human Health Intercontinental  responsible for the Companys
prescription drug business in Europe, the Middle East, Africa, Latin America and Canada
and worldwide human health marketingJanuary, 1997  President, Human Health-Europe, Middle East & Africa  responsible for the
Companys prescription drug business in Europe, the Middle East and Africa and worldwide
human health marketing
  37




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PART II
 
 Item 5. Market for Registrants Common Equity, Related Stockholder Matters and Issuer Purchases
of Equity Securities.
   Issuer Purchases of Equity SecuritiesTotal Number of
    
    ($ in millions)Total
    
    
    
    
    
    
    Shares Purchased
    
    Approx. Dollar ValueNumber
    
    
    Average
    
    
    as Part of
    
    Of Shares That May Yetof Shares
    
    
    Price Paid
    
    
    Publicly Announced
    
    Be Purchased Under thePeriod
    
    Purchased
    
    
    Per Share
    
    
    Plans or Programs
    
    Plans or ProgramsOctober 1
 October 31, 2005
    
    
    3,091,800
    
    
    $
    27.08
    
    
    
    3,091,800
    
    
    $
    7,697.3November 1
 November 30, 2005
    
    
    2,818,000
    
    
    $
    29.80
    
    
    
    2,818,000
    
    
    $
    7,613.4December 1 
 December 31, 2005
    
    
    2,729,600
    
    
    $
    30.63
    
    
    
    2,729,600
    
    
    $
    7,529.7Total
    
    
    8,639,400
    
    
    $
    29.09
    
    
    
    8,639,400
    
    
    $
    7,529.7
 
 Item 6. Selected Financial Data.
  
 Item 7. Managements Discussion and Analysis of Financial Condition and Results of Operations.
  
 Item 7A. Quantitative and Qualitative Disclosures About Market Risk.
  38




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Item 8. Financial Statements and Supplementary Data.
 (a) Financial Statements
  (b) Supplementary Data
  
 Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.
  
 Item 9A. Controls and Procedures.
  Internal Control  Integrated Framework Internal Control  Integrated Framework
  
 Item 9B. Other Information.
  
 PART III
 
 Item 10. Directors and Executive Officers of the Registrant.
  39




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##### Table of Contents



Our Values and Standards www.merck.com/about/corporategovernance
 
 Item 11. Executive Compensation.
  
 Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.
  
 Item 13. Certain Relationships and Related Transactions.
  
 Item 14. Principal Accountant Fees and Services.
  40




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##### Table of Contents



PART IV
 
 Item 15. Exhibits and Financial Statement Schedules.
 Documents filed as part of this Form 10-K
 1. Financial Statements
         2. Financial Statement Schedules
   3. Exhibits
 ExhibitNumber
    
    
    
    Description2.1
    
    
    
    Master Restructuring Agreement dated as of June 19, 1998 between Astra AB, Merck &
Co., Inc., Astra Merck Inc., Astra USA, Inc., KB USA, L.P., Astra Merck Enterprises,
Inc., KBI Sub Inc., Merck Holdings, Inc. and Astra Pharmaceuticals, L.P. (Portions of
this Exhibit are subject to a request for confidential treatment filed with the Commission)
 Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 19983.1
    
    
    
    Restated Certificate of Incorporation of Merck & Co., Inc. (October 1, 2004) 
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
September 30, 20043.2
    
    
    
    By-Laws of Merck & Co., Inc. (as amended effective May 24, 2005) 
Incorporated by reference to Current Report on Form 8-K dated May 24, 20054.1
    
    
    
    Indenture, dated as of April 1, 1991, between Merck & Co., Inc. and Morgan Guaranty Trust Company of New York,
as Trustee  Incorporated by reference to Exhibit 4 to Registration Statement on Form S-3 (No. 33-39349)4.2
    
    
    
    First Supplemental Indenture between Merck & Co., Inc. and First Trust of New York, National Association, as
Trustee  Incorporated by reference to Exhibit 4(b) to Registration Statement on Form S-3 (No. 333-36383)
 41




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##### Table of Contents



ExhibitNumber
    
    
    
    Description*10.1
    
    
    
    Executive Incentive Plan (as amended effective February 27, 1996) 3⁄4 Incorporated by
reference to Form 10-K Annual Report for the fiscal year ended December 31, 1995*10.2
    
    
    
    Base Salary Deferral Plan (as adopted on October 22, 1996, effective January 1, 1997)
3⁄4 Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 1996*10.3
    
    
    
    Merck & Co., Inc. Deferral Program (amended and restated as of December 15, 2005) 3⁄4 Incorporated by
reference to Current Report on Form 8-K dated December 16, 2005*10.4
    
    
    
    1991 Incentive Stock Plan (as amended effective February 23, 1994) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended December 31, 1994*10.5
    
    
    
    1996 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004*10.6
    
    
    
    2001 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004*10.7
    
    
    
    2004 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004*10.8
    
    
    
    Merck & Co., Inc. Change in Control Separation Benefits Plan  Incorporated by reference to Current Report on Form 8-K dated November
23, 2004*10.9
    
    
    
    Non-Employee Directors Stock Option Plan (as amended and restated
February 24, 1998) 3⁄4 Incorporated by reference to Form 10-K Annual Report for
the fiscal year ended December 31, 1997*10.10
    
    
    
    1996 Non-Employee Directors Stock Option Plan (as amended April 27, 1999) 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 1999*10.11
    
    
    
    2001 Non-Employee Directors Stock Option Plan (as amended April 19, 2002) 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 2002*10.12
    
    
    
    Supplemental Retirement Plan (as amended effective January 1, 1995) 3⁄4 Incorporated
by reference to Form 10-K Annual Report for the fiscal year ended December 31, 1994*10.13
    
    
    
    Retirement Plan for the Directors of Merck & Co., Inc. (amended and restated
June 21, 1996) 3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for
the period ended June 30, 1996
 
 *
    
    Management contract or compensatory plan or
arrangement. 42




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##### Table of Contents



ExhibitNumber
    
    
    
    Description*10.14
    
    
    
    Plan for Deferred Payment of Directors Compensation (amended and restated as of
May 31, 2005) 3⁄4 Incorporated by reference to Current Report on Form 8-K dated
May 24, 200510.15
    
    
    
    Limited Liability Company Agreement of Merck Capital Ventures, LLC (dated as of
November 27, 2000) 3⁄4 Incorporated by reference to Form 10-K Annual Report for the fiscal year
ended December 31, 2000*10.16
    
    
    
    Offer Letter between Merck &
Co., Inc. and Peter S. Kim, dated December 15, 2000 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year
ended December 31, 200310.17
    
    
    
    Amended and Restated License and Option Agreement dated as of July 1, 1998 between
Astra AB and Astra Merck Inc.
3⁄4 Incorporated by reference to Form 10-Q Quarterly
Report for the period ended June 30, 199810.18
    
    
    
    KBI Shares Option Agreement dated as of July 1, 1998 by and among Astra AB,
Merck & Co., Inc. and Merck Holdings, Inc. 3⁄4 Incorporated by reference to Form
10-Q
Quarterly Report for the period ended June 30, 199810.19
    
    
    
    KBI-E Asset Option Agreement dated as of July 1, 1998 by and among
Astra AB,
Merck & Co., Inc., Astra Merck Inc. and Astra Merck Enterprises Inc. 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period
ended June 30, 199810.20
    
    
    
    KBI Supply Agreement dated as of July 1, 1998 between Astra Merck Inc. and Astra
Pharmaceuticals, L.P. (Portions of this Exhibit are subject to a request for confidential
treatment filed with the Commission) 3⁄4 Incorporated by reference to Form 10-Q
Quarterly Report for the period ended June 30, 199810.21
    
    
    
    Second Amended and Restated Manufacturing Agreement dated as of July
1, 1998 among Merck & Co., Inc., Astra AB, Astra Merck Inc. and Astra USA, Inc.
3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 199810.22
    
    
    
    Limited Partnership Agreement dated as of July 1, 1998 between KB USA, L.P. and KBI
Sub Inc. 3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for
the period ended June 30, 199810.23
    
    
    
    Distribution Agreement dated as of July 1, 1998 between Astra Merck Enterprises Inc.
and Astra Pharmaceuticals, L.P. 3⁄4 Incorporated by reference to Form 10-Q Quarterly
Report for the period ended June 30, 1998
 
 *
    
    Management contract or compensatory plan or
arrangement. 43




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##### Table of Contents



ExhibitNumber
    
    
    
    Description10.24
    
    
    
    Agreement to Incorporate Defined Terms dated as of June 19, 1998 between Astra AB,
Merck & Co., Inc., Astra Merck Inc., Astra USA, Inc., KB USA, L.P., Astra Merck
Enterprises Inc., KBI Sub Inc., Merck Holdings, Inc. and Astra Pharmaceuticals, L.P. 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 199812
    
    
    
    Computation of Ratios of Earnings to Fixed Charges13
    
    
    
    2005 Annual Report to stockholders (only those portions incorporated by reference in
this document are deemed filed)21
    
    
    
    Subsidiaries of Merck & Co., Inc.23
    
    
    
    Consent of Independent Registered Public Accounting Firm 3⁄4
Contained on page 46 of this Report24.1
    
    
    
    Power of Attorney24.2
    
    
    
    Certified Resolution of Board of Directors31.1
    
    
    
    Rule 13a-14(a)/15d-14(a) Certification of Chief Executive Officer31.2
    
    
    
    Rule 13a-14(a)/15d-14(a) Certification of Chief Financial Officer32.1
    
    
    
    Section 1350 Certification of Chief Executive Officer32.2
    
    
    
    Section 1350 Certification of Chief Financial Officer
  44




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##### Table of Contents



SIGNATURES
 Pursuant to the requirements of Section 13 or 15(d) 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.
 MERCK & CO., INC.Dated: March 13, 2006By      RICHARD T. CLARK(Chief Executive Officer and President)
 By
    
    CELIA A. COLBERTCelia A. Colbert(Attorney-in-Fact)
 Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been
signed below by the following persons on behalf of the registrant and in the capacities and on the
dates indicated.
 Signatures
    
    Title
    
    DateRICHARD T. CLARK
    

Chief Executive Officer and
President; Principal Executive Officer; Director
    
    March 13, 2006JUDY C. LEWENT
    

Executive
Vice President and Chief Financial Officer; Principal Financial Officer
    
    March 13, 2006RICHARD C. HENRIQUES, JR.
    

Vice President, Controller;
Principal Accounting Officer
    
    March 13, 2006LAWRENCE A. BOSSIDY
    
    Director
    
    March 13, 2006WILLIAM G. BOWEN
    
    Director
    
    March 13, 2006JOHNNETTA B. COLE
    
    Director
    
    March 13, 2006WILLIAM B. HARRISON, JR.
    
    DirectorWILLIAM N. KELLEY
    
    Director
    
    March 13, 2006ROCHELLE B. LAZARUS
    
    Director
    
    March 13, 2006THOMAS E. SHENK
    
    Director
    
    March 13, 2006ANNE M. TATLOCK
    
    DirectorSAMUEL O. THIER
    
    Director
    
    March 13, 2006WENDELL P. WEEKS
    
    Director
    
    March 13, 2006PETER C. WENDELL
    
    Director
    
    March 13, 2006
 Celia A. Colbert, by signing her name hereto, does hereby sign this document pursuant to
powers of attorney duly executed by the persons named, filed with the Securities and Exchange
Commission as an exhibit to this document, on behalf of such persons, all in the capacities and on
the date stated, such persons including a majority of the directors of the Company.
 By
    
    CELIA A. COLBERTCelia A. Colbert(Attorney-in-Fact)
 45




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##### Table of Contents



Exhibit 23
 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
   
 46




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##### Table of Contents



EXHIBIT INDEX
 ExhibitNumber
    
    
    
    Description2.1
    
    
    
    Master Restructuring Agreement dated as of June 19, 1998 between Astra AB, Merck &
Co., Inc., Astra Merck Inc., Astra USA, Inc., KB USA, L.P., Astra Merck Enterprises,
Inc., KBI Sub Inc., Merck Holdings, Inc. and Astra Pharmaceuticals, L.P. (Portions of
this Exhibit are subject to a request for confidential treatment filed with the Commission)
 Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 19983.1
    
    
    
    Restated Certificate of Incorporation of Merck & Co., Inc. (October 1, 2004) 
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
September 30, 20043.2
    
    
    
    By-Laws of Merck & Co., Inc. (as amended effective May 24, 2005) 
Incorporated by reference to Current Report on Form 8-K dated May 24, 20054.1
    
    
    
    Indenture, dated as of April 1, 1991, between Merck & Co., Inc. and Morgan Guaranty Trust Company of New York,
as Trustee  Incorporated by reference to Exhibit 4 to Registration Statement on Form S-3 (No. 33-39349)4.2
    
    
    
    First Supplemental Indenture between Merck & Co., Inc. and First Trust of New York, National Association, as
Trustee  Incorporated by reference to Exhibit 4(b) to Registration Statement on Form S-3 (No. 333-36383)*10.1
    
    
    
    Executive Incentive Plan (as amended effective February 27, 1996) 3⁄4 Incorporated by
reference to Form 10-K Annual Report for the fiscal year ended December 31, 1995*10.2
    
    
    
    Base Salary Deferral Plan (as adopted on October 22, 1996, effective January 1, 1997)
3⁄4 Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 1996*10.3
    
    
    
    Merck & Co., Inc. Deferral Program (amended and restated as of December 15, 2005) 3⁄4 Incorporated by
reference to Current Report on Form 8-K dated December 16, 2005*10.4
    
    
    
    1991 Incentive Stock Plan (as amended effective February 23, 1994) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended December 31, 1994*10.5
    
    
    
    1996 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004*10.6
    
    
    
    2001 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004
 
 *
    
    Management contract or compensatory plan or
arrangement. 47




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##### Table of Contents



ExhibitNumber
    
    
    
    Description*10.7
    
    
    
    2004 Incentive Stock Plan (amended and restated as of February 22, 2005) 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year ended
December 31, 2004*10.8
    
    
    
    Merck & Co., Inc. Change in Control Separation Benefits Plan
 Incorporated by reference to Current Report on Form 8-K dated November
23, 2004*10.9
    
    
    
    Non-Employee Directors Stock Option Plan (as amended and restated
February 24, 1998) 3⁄4 Incorporated by reference to Form 10-K Annual Report for
the fiscal year ended December 31, 1997*10.10
    
    
    
    1996 Non-Employee Directors Stock Option Plan (as amended April 27, 1999) 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 1999*10.11
    
    
    
    2001 Non-Employee Directors Stock Option Plan (as amended April 19, 2002) 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 2002*10.12
    
    
    
    Supplemental Retirement Plan (as amended effective January 1, 1995) 3⁄4 Incorporated
by reference to Form 10-K Annual Report for the fiscal year ended December 31, 1994*10.13
    
    
    
    Retirement Plan for the Directors of Merck & Co., Inc. (amended and restated
June 21, 1996) 3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for
the period ended June 30, 1996*10.14
    
    
    
    Plan for Deferred Payment of Directors Compensation (amended and restated as of
May 31, 2005) 3⁄4 Incorporated by reference to Current Report on Form 8-K dated
May 24, 200510.15
    
    
    
    Limited Liability Company Agreement of Merck Capital Ventures, LLC (dated as of
November 27, 2000) 3⁄4 Incorporated by reference to Form 10-K Annual Report for the fiscal year
ended December 31, 2000*10.16
    
    
    
    Offer Letter between Merck &
Co., Inc. and Peter S. Kim, dated December 15, 2000 3⁄4
Incorporated by reference to Form 10-K Annual Report for the fiscal year
ended December 31, 200310.17
    
    
    
    Amended and Restated License and Option Agreement dated as of July 1, 1998 between
Astra AB and Astra Merck Inc.
3⁄4 Incorporated by reference to Form 10-Q Quarterly
Report for the period ended June 30, 199810.18
    
    
    
    KBI Shares Option Agreement dated as of July 1, 1998 by and among Astra AB,
Merck & Co., Inc. and Merck Holdings, Inc. 3⁄4 Incorporated by reference to Form
10-Q
Quarterly Report for the period ended June 30, 1998
 
 *
    
    Management contract or compensatory plan or
arrangement. 48




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##### Table of Contents



ExhibitNumber
    
    
    
    Description10.19
    
    
    
    KBI-E Asset Option Agreement dated as of July 1, 1998 by and among Astra AB,
Merck & Co., Inc., Astra Merck Inc. and Astra Merck Enterprises Inc. 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period
ended June 30, 199810.20
    
    
    
    KBI Supply Agreement dated as of July 1, 1998 between Astra Merck Inc. and Astra
Pharmaceuticals, L.P. (Portions of this Exhibit are subject to a request for confidential
treatment filed with the Commission) 3⁄4 Incorporated by reference to Form 10-Q
Quarterly Report for the period ended June 30, 199810.21
    
    
    
    Second Amended and Restated Manufacturing Agreement dated as of July
1, 1998 among Merck & Co., Inc., Astra AB, Astra Merck Inc. and Astra USA, Inc.
3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 199810.22
    
    
    
    Limited Partnership Agreement dated as of July 1, 1998 between KB USA, L.P. and KBI
Sub Inc. 3⁄4 Incorporated by reference to Form 10-Q Quarterly Report for
the period ended June 30, 199810.23
    
    
    
    Distribution Agreement dated as of July 1, 1998 between Astra Merck Enterprises Inc.
and Astra Pharmaceuticals, L.P. 3⁄4 Incorporated by reference to Form 10-Q Quarterly
Report for the period ended June 30, 199810.24
    
    
    
    Agreement to Incorporate Defined Terms dated as of June 19, 1998 between Astra AB,
Merck & Co., Inc., Astra Merck Inc., Astra USA, Inc., KB USA, L.P., Astra Merck
Enterprises Inc., KBI Sub Inc., Merck Holdings, Inc. and Astra Pharmaceuticals, L.P. 3⁄4
Incorporated by reference to Form 10-Q Quarterly Report for the period ended
June 30, 199812
    
    
    
    Computation of Ratios of Earnings to Fixed Charges13
    
    
    
    2005 Annual Report to stockholders (only those portions incorporated by reference in
this document are deemed filed)21
    
    
    
    Subsidiaries of Merck & Co., Inc.23
    
    
    
    Consent of Independent Registered Public Accounting Firm 3⁄4
Contained on page 46 of this Report24.1
    
    
    
    Power of Attorney24.2
    
    
    
    Certified Resolution of Board of Directors31.1
    
    
    
    Rule 13a-14(a)/15d-14(a) Certification of Chief Executive Officer31.2
    
    
    
    Rule 13a-14(a)/15d-14(a) Certification of Chief Financial Officer32.1
    
    
    
    Section 1350 Certification of Chief Executive Officer32.2
    
    
    
    Section 1350 Certification of Chief Financial Officer
 49