DEFERRAL PROGRAM

Exhibit 10.1

MERCK & CO., INC.

DEFERRAL PROGRAM

(Amended and Restated as of December 15, 2005)

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MERCK & CO., INC. DEFERRAL PROGRAM

The Deferral Program (“the Program”) is intended to permit a select group of management to defer income which would otherwise be immediately payable to them as annual base salary or under various incentive plans of Merck & Co., Inc. (“the Company”).

I. ADMINISTRATION

This Program is administered by the Compensation and Benefits Committee of the Company’s Board of Directors. This Committee is composed of non-employee directors only. The Committee shall have responsibility for determining which investments will be available under the Program, and those investments shall be listed on Schedule I hereto. The Committee shall review the investment selections at least once every five years. The Committee shall make all decisions affecting the timing, price or amount of any and all of the Deferred Compensation of participants subject to Section 16 of the Securities Exchange Act of 1934, as amended (“Section 16 Officers”), but may otherwise delegate any of its authority under this Program.

II. ELIGIBILITY

Eligibility to defer under this Program will be determined in accordance with the terms of the Company’s Base Salary Deferral Plan and various incentive plans. However, the Committee has the authority to refuse to permit an employee to participate in this Program, if the Committee determines that such participation would jeopardize the Program’s compliance with applicable law or the Program’s status as a top hat plan under the Employee Retirement Income Security Act.

III. DEFERRAL INTO A DEFERRED COMPENSATION ACCOUNT

A.  Election to Defer

A participant’s decision to defer under the Program must be made, (i) for the Base Salary Deferral Plan, prior to the commencement of the pay period during which the base salary to be deferred will be earned, (ii) for annual incentive plans, prior to the commencement of the performance year during which the bonus monies to be deferred will be earned, and (iii) for long-term incentive plans, prior to the commencement of the last year of the award period during which the bonus monies to be deferred will be earned. For purposes of annual incentive plans only, a participant who is hired by the Company during a performance year may make an election, no later than the thirtieth (30 ^th ) day from the participant’s date of hire, to defer bonus monies to be earned during such performance year. For the Base Salary Deferral Plan, only amounts equal to or in excess of five percent (5%) of Annual Base Salary (as defined in the Base Salary Deferral Plan) and less than or equal to the lesser of (1) fifty percent (50%) of Annual Base Salary or (2) the Participant’s Annual Base Salary in excess of the amount determined under Section 401(a)(17) of the Internal Revenue Code may be deferred. For the annual and long-term incentive plans, only amounts in excess of $3,000 may be deferred. Amounts so deferred are known as “Deferred Compensation” and will be credited to the participant’s “Deferred Compensation Account.” Deferred Compensation shall be held in one account regardless of the plan (Base Salary Deferral or incentive plan) under which it was deferred.

B.  Election of Distribution Schedule

1. Timing of Election

The participant shall also elect a distribution schedule for his/her Deferred Compensation. A participant’s election of a distribution schedule in connection with a deferral election under annual and/or long-term incentive plans shall be made at the same time that the participant makes the election to defer. A participant’s initial election of a distribution schedule in connection with deferrals under the Base Salary Deferral Plan shall be made at the same time as the initial deferral election, shall be irrevocable during the calendar year for which it was made and shall apply to all deferrals of Annual Base Salary until a new distribution election becomes effective. Thereafter, an election of a different distribution schedule in connection with deferrals under the Base Salary Deferral Plan may be made at any time, provided, however, that such new distribution schedule shall only apply prospectively to deferrals of Annual Base Salary in the following calendar year.

2. Distribution Schedule

A participant may elect to have payments begin at the participant’s actual retirement date, subsequent to that date or prior thereto. A participant may elect a lump sum or a schedule of annual installments, up to a maximum of 15 annual installments. No installment, however, may be payable more than fifteen years after the participant’s termination of employment.

C.  Election of Investment Alternatives

The participant shall designate, in accordance with procedures established by the Company for such designation, the portion (in multiples of 1%) of the Deferred Compensation to be allocated to any investment alternative available under this Program.

IV. VALUATION OF DEFERRED COMPENSATION ACCOUNTS

A.  Common Stock

1. Initial Crediting

The amount allocated to Merck Common Stock shall be used to determine the number of full and partial shares of Merck Common Stock which such amount would purchase at the closing price of Merck Common Stock on the New York Stock Exchange on the date cash payments of base salary, for amounts deferred under the Base Salary Deferral Plan, or incentive awards, for amounts deferred under the various incentive plans, would otherwise be paid to the participant (“the Deferral Date”). Should the Committee determine that valuation on any Deferral Date would not constitute fair market value, then the Committee shall decide on which date fair market value shall be determined using the valuation method set forth in this paragraph. The Company shall credit the participant’s Deferred Compensation Account with the number of full and partial shares of Merck Common Stock so determined. However, at no time prior to the delivery of such shares shall any shares be purchased or earmarked for such Account and the participant shall not have any of the rights of a shareholder with respect to shares credited to his/her Deferred Compensation Account.

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2. Dividends

The Company shall credit the Participant’s Deferred Compensation Account with the number of full and partial shares of Merck Common Stock purchasable at the closing price of Merck Common Stock on the New York Stock Exchange as of the date each dividend is paid on the Common Stock, with the dividends which would have been paid on the number of shares credited to such Account (including pro rata dividends on any partial share) had the shares so credited then been issued and outstanding.

3. Redesignations

The value of Merck Common Stock for purposes of redesignation shall be the closing price of Merck Common Stock on the New York Stock Exchange on (i) the day when the redesignation request is received pursuant to administrative guidelines established by the Human Resources Financial Services area of the Treasury department, provided the request is received prior to the close of the New York Stock Exchange on such day or (ii) the next following business day if the request is received when the New York Stock Exchange is closed.

4. Distributions

Distributions of Merck Common Stock will be valued at the closing price of Merck Common Stock on the New York Stock Exchange on the distribution date.

5. Limitations

Shares of Merck Common Stock to be delivered under the provisions of this Program may be delivered by the Company from its authorized but unissued shares of Common Stock or from Common Stock held in the treasury. The amount of shares available each year under this Program shall be one-tenth of one-percent of outstanding shares of Merck Common Stock on the last business day of the preceding calendar year plus any shares authorized under this Program in previous years but not used, minus any shares distributed under the Executive Incentive Plan after April 26, 1994.

6. Adjustments

In the event of a reorganization, recapitalization, stock split, stock dividend, combination of shares, merger, consolidation, rights offering or any other change in the corporate structure or shares of the Company, the number and kind of shares of Merck Common Stock available under this Program or credited to participants’ Deferred Compensation Accounts shall be adjusted accordingly.

B.  Mutual Funds

1. Initial Crediting

The amount allocated to each Mutual Fund shall be used to determine the number of full and partial Mutual Fund shares that such amount would purchase at the closing net asset value of the Mutual Fund shares on the Deferral Date. The Company shall credit the participant’s Deferred Compensation Account with the number of full and partial Mutual Fund shares so determined. However, no Mutual Fund shares shall be purchased or earmarked for such Account, nor shall the participant have the rights of a shareholder with respect to such Mutual Fund shares.

2. Dividends

The Company shall credit the participant’s Deferred Compensation Account with the number of full and partial Mutual Fund shares purchasable, at the closing net asset value of the Mutual Fund shares as of the date each dividend is paid on the Mutual Fund shares, with the dividends which would have been paid on the number of shares credited to such Account (including pro rata dividends on any partial share) had the shares then been owned by the participant for purposes of the above computation.

3. Redesignations

The value of Mutual Fund shares for purposes of redesignation shall be the net asset value of such Mutual Fund at the close of business on (i) the day when the redesignation request is received pursuant to administrative guidelines established by the Human Resources Financial Services area of the Treasury department, provided the request is received prior to the close of the New York Stock Exchange on such day or (ii) the next following business day if the request is received when the New York Stock Exchange is closed.

4. Distributions

Mutual Fund distributions will be valued based on the closing net asset value of the Mutual Fund shares on the distribution date.

5. Adjustments

In the event of a reorganization, recapitalization, stock split, stock dividend, combination of shares, merger, consolidation, rights offering or any other change in the corporate structure or shares of a Mutual Fund, the number and kind of shares of that Mutual Fund credited to participants’ Deferred Compensation Accounts shall be adjusted accordingly.

V. REDESIGNATION WITHIN A DEFERRED COMPENSATION ACCOUNT

A.  Basic Redesignation Rules

A participant, or the beneficiary or legal representative of a deceased participant, may redesignate amounts credited to a Deferred Compensation Account among the investments available under this Program in accordance with the following rules:

B.  Special Rules for Redesignation Out of C