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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VVT3eeSA+jgo15jyspgjs31j2y2NBEpEMR56uk9iG+EH4zOAK6AyVVfbqJ4uA2Uy
 0phY+nMOal0IscaIQMdGxw==

<SEC-DOCUMENT>0001209191-03-021701.txt : 20030916
<SEC-HEADER>0001209191-03-021701.hdr.sgml : 20030916
<ACCEPTANCE-DATETIME>20030916102853
ACCESSION NUMBER:		0001209191-03-021701
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030912
FILED AS OF DATE:		20030916

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MERCK & CO INC
		CENTRAL INDEX KEY:			0000064978
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				221109110
		STATE OF INCORPORATION:			NJ
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE MERCK DR
		STREET 2:		P O BOX 100
		CITY:			WHITEHOUSE STATION
		STATE:			NJ
		ZIP:			08889-0100
		BUSINESS PHONE:		9084234044

	MAIL ADDRESS:	
		STREET 1:		ONE MERCK DR
		STREET 2:		PO BOX 100 WS3AB-05
		CITY:			WHITEHOUSE STATION
		STATE:			NJ
		ZIP:			08889-0100

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			THIER SAMUEL O MD
		CENTRAL INDEX KEY:			0001144773

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-03305
		FILM NUMBER:		03896834

	BUSINESS ADDRESS:	
		STREET 1:		C/O CHARLES RIVER LABORATORIES
		STREET 2:		251 BALLARDVALE ST
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887
		BUSINESS PHONE:		9786586000

	MAIL ADDRESS:	
		STREET 1:		C/O CHARLES RIVER LABORATORIES
		STREET 2:		251 BALLARDVALE ST
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?><ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-09-12</periodOfReport><notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000064978</issuerCik>
        <issuerName>MERCK &amp; CO INC</issuerName>
        <issuerTradingSymbol>(MRK)</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001144773</rptOwnerCik>
            <rptOwnerName>THIER SAMUEL O MD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MASSACHUSETTS GENERAL HOSPITAL</rptOwnerStreet1>
            <rptOwnerStreet2>55 FRUIT ST., BULFINCH 370</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02114-2606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Phantom Stock</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F1" /></conversionOrExercisePrice><transactionDate><value>2003-09-12</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>22.4299</value></transactionShares><transactionPricePerShare><value>53.5</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2" /></exerciseDate><expirationDate><footnoteId id="F2" /></e
xpirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>22.4299</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6567.051</value><footnoteId id="F3" /><footnoteId id="F4" /></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">1-for-1</footnote><footnote id="F2">Phantom stock units are to be settled 100% in cash upon reporting person's termination of service in accordance with a distribution schedule elected pursuant to the terms of the Plan for Deferred Payment of Director's Compensation.</footnote><footnote id="F3">Holdings include shares acquired in dividend reinvestment transactions.</footnote><footnote id="F4">Number of shares and prices adjusted to reflect spin-off of
 Medco Health Solutions, Inc. on August 19, 2003.</footnote></footnotes><remarks></remarks><ownerSignature><signatureName>Nancy V. Van Allen as Attorney-in-Fact for
Samuel O. Thier</signatureName><signatureDate>2003-09-16</signatureDate></ownerSignature></ownershipDocument>

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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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