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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 LzZmQOjXSxrxjb5YrFIVDIZdSSegbJcITmrTNRqbBOAfaC1XpF/QMCMLtWP8ULY/
 Iz+oNroycEzZKqL6qytm4w==

<SEC-DOCUMENT>0001022079-04-000006.txt : 20040105
<SEC-HEADER>0001022079-04-000006.hdr.sgml : 20040105
<ACCEPTANCE-DATETIME>20040105161456
ACCESSION NUMBER:		0001022079-04-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040101
FILED AS OF DATE:		20040105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FLAHERTY JAMES F III
		CENTRAL INDEX KEY:			0001201560

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12215
		FILM NUMBER:		04505149

	BUSINESS ADDRESS:	
		STREET 1:		4675 MACARTHUR COURT
		CITY:			NEWPORT BEACH
		STATE:			CA
		ZIP:			92660

	MAIL ADDRESS:	
		STREET 1:		C/O QUEST DIAGNOSTICS INC
		STREET 2:		ONE MALCOLM AVE
		CITY:			TETERBORO
		STATE:			NJ
		ZIP:			07608

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			QUEST DIAGNOSTICS INC
		CENTRAL INDEX KEY:			0001022079
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MEDICAL LABORATORIES [8071]
		IRS NUMBER:				161387862
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE MALCOLM AVE
		CITY:			TETERBORO
		STATE:			NJ
		ZIP:			07608
		BUSINESS PHONE:		2013935000

	MAIL ADDRESS:	
		STREET 1:		ONE MALCOLM AVE
		CITY:			TETERBORO
		STATE:			NJ
		ZIP:			07601

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CORNING CLINICAL LABORATORIES INC
		DATE OF NAME CHANGE:	19960903
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001201560d20040105f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2004-01-01</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0001022079</issuerCik><issuerName>QUEST DIAGNOSTICS INC</issuerName>        <issuerTradingSymbol>DGX</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001201560</rptOwnerCik><rptOwnerName>FLAHERTY JAMES F III</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>ONE MALCOLM AVENUE</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>TETERBORO</rptOwnerCity><rptOwnerState>NJ</rptOwnerState><rptOwnerZipCode>07608</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle></officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><nonDerivativeTable
><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Stock Options (Right to buy)</value></securityTitle><conversionOrExercisePrice><value>73.19</value></conversionOrExercisePrice><transactionDate><value>2004-01-01</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>695</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><tra
nsactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-01-01</value></exerciseDate><expirationDate><value>2014-01-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>695</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>695</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes></footnotes><ownerSignature><signatureName>Leo C. Farrenkopf, Jr.</signatureName><signatureDate>2004-01-05</signatureDate></ownerSignature></ownershipDocument>

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</SEC-DOCUMENT>
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