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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,
 CY3U6w6d3nViuputZHKeMaBKMFTU3MOTmu/9UOYOULD8EmqvJ5TVMCBzlvdT8/PP
 jcSzOcatB+0SSIZ1uG735g==

<SEC-DOCUMENT>0000062709-04-000008.txt : 20040120
<SEC-HEADER>0000062709-04-000008.hdr.sgml : 20040119
<ACCEPTANCE-DATETIME>20040120215317
ACCESSION NUMBER:		0000062709-04-000008
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040115
FILED AS OF DATE:		20040120

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GROVES RAY J
		CENTRAL INDEX KEY:			0001104959

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05998
		FILM NUMBER:		04533764

	BUSINESS ADDRESS:	
		STREET 1:		100 TREDEGAR ST
		CITY:			RICHMOND
		STATE:			VA
		ZIP:			23219

	MAIL ADDRESS:	
		STREET 1:		P O BOX 26532
		CITY:			RICHMOND
		STATE:			VA
		ZIP:			23261

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MARSH & MCLENNAN COMPANIES INC
		CENTRAL INDEX KEY:			0000062709
		STANDARD INDUSTRIAL CLASSIFICATION:	INSURANCE AGENTS BROKERS & SERVICES [6411]
		IRS NUMBER:				362668272
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1166 AVENUE OF THE AMERICAS
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10036
		BUSINESS PHONE:		2123455000

	MAIL ADDRESS:	
		STREET 1:		1166 AVENUE OF THE AMERICAS
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10036

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MARLENNAN CORP
		DATE OF NAME CHANGE:	19760505
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2004-01-15</periodOfReport>
    <issuer>
        <issuerCik>0000062709</issuerCik>
        <issuerName>MARSH &amp; MCLENNAN COMPANIES INC</issuerName>
        <issuerTradingSymbol>MMC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001104959</rptOwnerCik>
            <rptOwnerName>GROVES RAY J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1166 AVENUE OF THE AMERICAS</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036-2774</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>CHIEF EXEC OFFICER, MARSH INC.</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>155.1633</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>21291.172</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><va
lue>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2003-09-30</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>34.1319</value><footnoteId id="F3"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>34.1319</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>STOCK INVESTMENT PLAN (401K)</value></natureOfOwnership></o
wnershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>RESTRICTED STOCK UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F5"/></conversionOrExercisePrice><transactionDate><value>2004-01-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>16971</value></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F6"/></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>16971</value></underlyingSecurityShares></underlyingSecurity><postTra
nsactionAmounts><sharesOwnedFollowingTransaction><value>80558</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>SISP RS UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F5"/></conversionOrExercisePrice><transactionDate><value>2003-09-30</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>214.7501</value><footnoteId id="F4"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F6"/></exerciseDate><expirat
ionDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>214.7501</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>346.0699</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Aggregate of 155.1633 shares acquired at quarterly dividend payment dates pursuant to MMC's dividend reinvestment plan administered by the Bank of New York.</footnote><footnote id="F2">Includes 11,568 shares of restricted stock.</footnote><footnote id="F3">Reflects additional shares acquired by the Stock Investment Plan (SIP) Custodian at prevailing market prices.  Information reported herein is based on reporting person'
s Plan Statement as of September 30, 2003.</footnote><footnote id="F4">Reflects additional shares acquired by the Stock Investment Supplemental Plan (SISP) Custodian at prevailing market prices.  Information reported herein is based on reporting person's Plan Statement as of September 30, 2003.</footnote><footnote id="F5">The security converts to common stock on a one-for-one basis.</footnote><footnote id="F6">Not Applicable.</footnote></footnotes><remarks/><ownerSignature><signatureName>WILLIAM J. WHITE,  Attorney-in-fact</signatureName><signatureDate>2004-01-20</signatureDate></ownerSignature></ownershipDocument>

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