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                                                            Exhibit 10.25

                                SECOND AMENDMENT

                                       TO

                       THE QUEST DIAGNOSTICS INCORPORATED

                     SUPPLEMENTAL DEFERRED COMPENSATION PLAN

         Quest Diagnostics Incorporated (the "Employer") has adopted the
following Second Amendment to the Quest Diagnostics Incorporated Supplemental
Deferred Compensation Plan (the "Plan"), effective as specifically indicated.

                               W I T N E S S E T H

         WHEREAS, Section 8.1 of the Plan permits the Employer to amend the
Plan; and

         WHEREAS, the Employer desires to amend the Plan, effective January 1,
2002, to reflect an administrative change in the commencement date of deferrals
and to change the period of suspension of deferrals from 12 months to six months
for a Participant who has made a hardship withdrawal under the Profit Sharing
Plan of Quest Diagnostics Incorporated; and effective January 1, 2003, to change
the formula for crediting Employer Contributions and to provide that no portion
of an Employer Contribution credited on or after January 1, 2003 will
automatically be treated as though invested in Employer Stock, but that the
portion of Employer Contributions credited before January 1, 2003 that was
treated as though invested in Employer Stock will continue to be so treated.

         NOW, THEREFORE, the Plan is amended as follows:


                                  FIRST CHANGE

         Effective January 1, 2002, Section 3.1(c) (as it read under the First
Amendment to the Plan) shall be deleted in its entirety and the following shall
be substituted in lieu thereof:

(c)      A salary reduction agreement shall become effective on the first day of
         the period as set forth in the Participant's election. The election
         will be effective to defer Compensation relating to


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         all services performed in the Plan Year subsequent to the filing of
         such an election. Any subsequent election will be effective as of the
         first day of the following Plan Year and will apply only to
         Compensation payable with respect to services rendered after such date.
         Amounts credited to a Participant's Account prior to the effective date
         of any subsequent election will not be affected.

         If a Participant's Compensation for a Plan Year goes above the Section
         401(a)(17) Limit on account of payment of non-Bonus Compensation, then
         deferrals pursuant to his election shall commence as of the payroll
         period coincident with or next following the payroll period in which
         the Participant's Compensation goes above the Section 401(a)(17) Limit.
         If a Participant's Compensation for a Plan Year goes above the Section
         401(a)(17) Limit on account of payment of Bonus, then deferrals
         pursuant to his election shall commence as of the payroll period in
         which the Participant's Compensation goes above the Section 401(a)(17)
         Limit (but deferrals shall be made only on Compensation in excess of
         the Section 401(a)(17) Limit).

         Subject to the claims of the Employee's creditors in the event of the
         Employer's insolvency, a Participant shall have a nonforfeitable right
         to his Deferral Contributions.


                                  SECOND CHANGE

         Effective January 1, 2002, Section 3.1(d) (as it read under the First
Amendment to the Plan) shall be deleted in its entirety and the following shall
be substituted in lieu thereof:

(d)      The Employer shall credit an amount to the Account maintained on behalf
         of the Participant corresponding to the amount of said reduction. Under
         no circumstances may an election to defer Compensation be adopted
         retroactively. A Participant may not revoke or change an election to
         defer Compensation for a Plan Year during that year; provided, however,
         that a Participant who has made a hardship withdrawal under the Profit
         Sharing Plan of Quest Diagnostics Incorporated may not defer
         Compensation under this Plan for a period of six months from the date
         of the withdrawal.


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                                  THIRD CHANGE

         Effective January 1, 2003, Section 3.2 (as it read under the First
Amendment to the Plan) shall be deleted in its entirety and the following shall
be substituted in lieu thereof:

3.2. EMPLOYER CONTRIBUTIONS.

The Employer shall credit an Employer Contribution to the Account maintained on
behalf of each Participant who had Deferral Contributions made on his behalf
during a payroll period. Notwithstanding the preceding sentence, no Employer
Contribution shall be credited to a Participant who is also a participant in the
Quest Diagnostics Transferee Pension Plan. The amount of the Employer
Contribution to be credited on behalf of a Participant who is not a Senior
Executive shall be equal to 100% of the Deferral Contributions made on behalf of
the Participant with respect to such payroll period, but taking into account
only those Deferral Contributions made at a rate that does not exceed four (4)
percent of the Participant's Compensation in excess of the Section 401(a)(17)
Limit. The amount of the Employer Contribution to be credited on behalf of a
Participant who is a Senior Executive shall be equal to 100% of the Deferral
Contributions made on behalf of the Participant with respect to such payroll
period pursuant to Section 3.1(b)(1), but taking into account only those
Deferral Contributions made at a rate that does not exceed four (4) percent of
the Participant's Compensation (excluding any Bonus deferred pursuant to Section
3.1(b)(2)) in excess of the Section 401(a)(17) Limit. In addition, with respect
to the payroll period in which any portion of a Senior Executive's Bonus is
deferred pursuant to Section 3.1(b)(2), an additional Employer Contribution
shall be credited on behalf of the Senior Executive in an amount equal to 100%
of the Deferral Contributions made on behalf of the Participant pursuant to
Section 3.1(b)(2), but taking into account only those Deferral Contributions
that do not exceed four (4) percent of the Participant's Bonus deferred pursuant
to Section 3.1(b)(2). Subject to the claims of the Employer's creditors in the
event of the Employer's insolvency, a Participant shall have a nonforfeitable
right to Employer Contributions made on his behalf.


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                                  FOURTH CHANGE

         Effective January 1, 2003, the first paragraph of Section 5.2 shall be
deleted in its entirety and the following shall be substituted in lieu thereof:

Investments in which the Accounts of Participants shall be treated as invested
and reinvested shall be directed by the Employer or by each Participant, or
both. No portion of the Employer Contributions credited to a Participant's
Account on or after January 1, 2003 shall automatically be treated as though
invested in Employer Stock, but the portion of the Employer Contributions
credited to a Participant's Account before January 1, 2003 that was
automatically treated as though invested in Employer Stock shall continue, on
and after January 1, 2003, to be treated as though invested in Employer Stock.

         IN ALL OTHER RESPECTS, said Plan is hereby ratified and confirmed.


         IN WITNESS WHEREOF, the Employer has caused this Second Amendment to be
executed by its duly authorized officer on this 16th day of December, 2002.



WITNESS:                                QUEST DIAGNOSTICS INCORPORATED




/s/ Leo C. Farrenkopf, Jr.               By: /s/ Richard L. Bevan
-------------------------------          -----------------------------------





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