<SUBMISSION>
<ACCESSION-NUMBER>0001022079-04-000100
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20040504
<FILING-DATE>20040506
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BUEHLER WILLIAM F
<CIK>0001222669
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-12215
<FILM-NUMBER>04784783
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>QUEST DIAGNOSTICS INC
<STREET2>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07608
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>QUEST DIAGNOSTICS INC
<CIK>0001022079
<ASSIGNED-SIC>8071
<IRS-NUMBER>161387862
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07608
<PHONE>2013935000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE MALCOLM AVE
<CITY>TETERBORO
<STATE>NJ
<ZIP>07601
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>CORNING CLINICAL LABORATORIES INC
<DATE-CHANGED>19960903
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001022079</issuerCik>
        <issuerName>QUEST DIAGNOSTICS INC</issuerName>
        <issuerTradingSymbol>DGX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001222669</rptOwnerCik>
            <rptOwnerName>BUEHLER WILLIAM F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5147</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>85.25</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-05-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-05-04</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-05-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <ownerSignature>
        <signatureName>Sirisha Gummaregula, for William F. Buehler</signatureName>
        <signatureDate>2004-05-06</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>buehlerpoa-41504.txt
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
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 15th day of
April, 2004.

	/s/ William Buehler
	Signature
	WILLIAM F. BUEHLER



STATE OF SOUTH CAROLINA	)
	  	        ):  ss.
COUNTY OF CHARLESTON    )

	On this 15th day of April, 2004, before me, the subscriber,
personally appeared WILLIAM F. BUEHLER, 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/Jennifer J. Wardlaw
	Notary Public
	My Commission Expires
	January 7, 2010

</TEXT>
</DOCUMENT>
</SUBMISSION>
