POWER OF ATTORNEY


	Know all by these presents, that the undersigned
hereby constitutes and appoints each of Sirisha Gummaregula,
Michael E. Prevoznik, and Leo C. Farrenkopf, Jr., signing
singly, the undersigned's true and lawful attorney-in-fact
to:

(1)	execute for and on behalf of the undersigned, in
the undersigned's capacity as an executive officer and/or
director of Quest Diagnostics Incorporated (the "Company"),
Form ID Applications and Forms 3, 4 and 5 in accordance
with Section 16(a) of the Securities Exchange Act of 1934
and the rules thereunder;

(2)	do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to
complete and execute any such Form ID Application, Form 3,
4 or 5, complete and execute any amendment or amendments
thereto, and timely  file such form with the United States
Securities and Exchange Commission and any other authority;
and

(3)	take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of such
attorney-in-fact, may be of benefit to, in the best interest
of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact
on behalf of the undersigned pursuant to this Power of Attorney
shall be in such form and shall contain such terms and
conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

	The undersigned hereby grants to each such attorney-
in-fact full power and authority to do and perform all and
every act and thing whatsoever requisite, necessary and proper
to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full
power of substitution or revocation, hereby ratifying and
confirming all that such attorney-in-fact, or such attorney
-in-fact's substitute or substitutes, shall lawfully do or
cause to be done by virtue of this power of attorney and the
rights and powers herein granted.  The undersigned acknowledges
that the foregoing attorneys-in-fact, in serving in such
capacity at the request of the undersigned, are not assuming,
nor is the company assuming, any of the undersigned's
responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.

	This Power of Attorney shall remain in full force
and effect until the undersigned is no longer required to
file Forms 3, 4, and 5 with respect to the undersigned's
holdings of and transactions in securities issued by the
Company, unless earlier revoked by the undersigned in a
signed writing delivered to the foregoing attorneys-
in-fact.

	IN WITNESS WHEREOF, the undersigned has caused
this Power of Attorney to be executed as of this 20th
day of April, 2004.


	/s/William R. Grant
	Signature
	WILLIAM R. GRANT



STATE OF NEW YORK	)
			):  ss.
COUNTY OF NASSAU	)

	On this 20th day of April, 2004, before me, the
subscriber, personally appeared WILLIAM R. GRANT, to me
and known to me to be the same person described in and
who executed the foregoing instrument, and he duly
acknowledged to me that he executed the same.


	/s/Paula G. Semelmacher
	Notary Public
	Notary Public, State of New York
	No. 01SE6004120
	Qualified in Nassau County
	Commission Expires March 16, 2006

