-----BEGIN PRIVACY-ENHANCED MESSAGE-----
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,
 Sx6URps+bpg3GYH9Rpb8kUD2y8YdZA1b+c+gZ/5Skj/E5cYD/EAMh0aFCy7Gx6tF
 Z/8OlUxwfM+IkKh4rZnshA==

<SEC-DOCUMENT>0000062709-04-000010.txt : 20040120
<SEC-HEADER>0000062709-04-000010.hdr.sgml : 20040119
<ACCEPTANCE-DATETIME>20040120215625
ACCESSION NUMBER:		0000062709-04-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030828
FILED AS OF DATE:		20040120

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CABIALLAVETTA MATHIS
		CENTRAL INDEX KEY:			0001191065

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05998
		FILM NUMBER:		04533766

	BUSINESS ADDRESS:	
		STREET 1:		ALTRIA GROUP INC
		STREET 2:		120 PARK AVE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		9176632256

	MAIL ADDRESS:	
		STREET 1:		ALTRIA GROUP INC
		STREET 2:		120 PARK AVE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
</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>2003-08-28</periodOfReport>
    <issuer>
        <issuerCik>0000062709</issuerCik>
        <issuerName>MARSH &amp; MCLENNAN COMPANIES INC</issuerName>
        <issuerTradingSymbol>MMC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191065</rptOwnerCik>
            <rptOwnerName>CABIALLAVETTA MATHIS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>IN DER BETHALDEN 10</rptOwnerStreet1>
            <rptOwnerStreet2>CH-8003 RUESCHILIKON</rptOwnerStreet2>
            <rptOwnerCity>SWITZERLAND</rptOwnerCity>
            <rptOwnerState>V8</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>VICE CHAIRMAN</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2004-01-18</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>3988</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><footnoteId id="F7"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>84885</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natu
reOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2004-01-18</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>F</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>747</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><value>47.915</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>84138</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransactio
n><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2003-08-27</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>290.675</value><footnoteId id="F3"/></transactionShares><transactionPricePerShare><footnoteId id="F7"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1735.1162</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>STOCK INVESTMENT PLAN (401K)</value></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>COMMON</value></securityTitle><transactionDate><value>2003-08-28<
/value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1520.9994</value><footnoteId id="F4"/></transactionShares><transactionPricePerShare><value>49.65</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>214.1168</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>STOCK INVESTMENT PLAN (401K)</value></natureOfOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>RESTRICTED STOCK UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F6"/></conversionOrExercisePri
ce><transactionDate><value>2004-01-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>25457</value></transactionShares><transactionPricePerShare><footnoteId id="F7"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F7"/></exerciseDate><expirationDate><footnoteId id="F7"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>25457</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>113091</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/>
</natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>RESTRICTED STOCK UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F6"/></conversionOrExercisePrice><transactionDate><value>2004-01-18</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>3988</value></transactionShares><transactionPricePerShare><footnoteId id="F7"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F7"/></exerciseDate><expirationDate><footnoteId id="F7"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>3988</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sha
resOwnedFollowingTransaction><value>109103</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="F6"/></conversionOrExercisePrice><transactionDate><value>2003-09-30</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1338.4162</value><footnoteId id="F5"/></transactionShares><transactionPricePerShare><footnoteId id="F7"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F7"/></exerciseDate><expirationDate><footnoteI
d id="F7"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>1338.4162</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5377.8074</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Vesting and distribution to reporting person of 3,988 shares of Restricted Stock Units of which 747 shares were withheld to cover applicable taxes.</footnote><footnote id="F2">Includes 593 shares acquired under the MMC Employee Stock Purchase Plan on September 30, 2003 and 68,500 shares of restricted stock.</footnote><footnote id="F3">Reflects shares held in Stock Investment Plan (SIP) as of August 27, 2003.</footnote><footnote id="F4">R
eflects diversification election of shares out of Stock Investment Plan (SIP) not previously reported on Form 4.</footnote><footnote id="F5">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="F6">The security converts to common stock on a one-for-one basis.</footnote><footnote id="F7">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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</DOCUMENT>
</SEC-DOCUMENT>
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