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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,
 I2zTh3vV0TAzk1q1YO1MZnUZQLesNUNpETZbiCK/ahvOjj75HZ9xq5l+RvpxI/0J
 UkWCL/iGZtrPyXRiX5LIrQ==

<SEC-DOCUMENT>0000062709-03-000151.txt : 20031118
<SEC-HEADER>0000062709-03-000151.hdr.sgml : 20031118
<ACCEPTANCE-DATETIME>20031118164023
ACCESSION NUMBER:		0000062709-03-000151
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031114
FILED AS OF DATE:		20031118

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ERBURU ROBERT F
		CENTRAL INDEX KEY:			0001194446

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05998
		FILM NUMBER:		031010866

	BUSINESS ADDRESS:	
		STREET 1:		TIMES MIRROR CO
		STREET 2:		202 WEST FIRST ST 6TH FL
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90012

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>2003-11-14</periodOfReport>
    <issuer>
        <issuerCik>0000062709</issuerCik>
        <issuerName>MARSH &amp; MCLENNAN COMPANIES INC</issuerName>
        <issuerTradingSymbol>MMC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194446</rptOwnerCik>
            <rptOwnerName>ERBURU ROBERT F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE TIMES MIRROR COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>220 WEST 1ST STREET</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90053</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>DIRECTORS STOCK PLAN (ANNEX) RS UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F4"/></conversionOrExercisePrice><transactionDate><value>2003-11-14</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>93.69</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><value>45.71</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value>
</underlyingSecurityTitle><underlyingSecurityShares><value>93.69</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>13908.74</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>DIRECTORS STOCK PLAN RS UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F4"/></conversionOrExercisePrice><transactionDate><value>2003-11-14</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>189.08</value><footnoteId id="F2"/></transactionShares><transactionPricePerShare><value>45.71</value></transactionPricePerShare><transactionAcquir
edDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>189.08</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>28069.71</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>DIRECTORS STOCK PLAN RS UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F4"/></conversionOrExercisePrice><transactionDate><value>2003-11-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCo
de><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>316.1</value><footnoteId id="F3"/></transactionShares><transactionPricePerShare><value>45.08</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>316.1</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>28385.81</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Acquired with dividend proce
eds credited to reporting person's account under the Marsh &amp; McLennan Directors Stock Compensation Plan (Annex).</footnote><footnote id="F2">Acquired with dividend proceeds credited to reporting person's account under the Marsh &amp; McLennan Directors Stock Compensation Plan.</footnote><footnote id="F3">Acquired upon issuance of shares for directors fees pursuant to the Marsh &amp; McLennan Directors Stock Compensation Plan.</footnote><footnote id="F4">The security converts to common stock on a one-for-one basis.</footnote><footnote id="F5">Not Applicable.</footnote></footnotes><remarks/><ownerSignature><signatureName>WILLIAM J. WHITE,  Attorney-in-fact</signatureName><signatureDate>2003-11-18</signatureDate></ownerSignature></ownershipDocument>

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