-----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,
 ToyMstrhnaa+546u3s0o69ZnWowtFbzpR1aBMQ2LfuI64aATATqmVYRegcs+oNdq
 dA7zFj1h3ZBNj5S8wIPgRA==

<SEC-DOCUMENT>0000062709-04-000005.txt : 20040120
<SEC-HEADER>0000062709-04-000005.hdr.sgml : 20040119
<ACCEPTANCE-DATETIME>20040120213839
ACCESSION NUMBER:		0000062709-04-000005
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:			DAVIS CHARLES A /NJ/
		CENTRAL INDEX KEY:			0001071287
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-HOME FURNITURE, FURNISHINGS & EQUIPMENT STORES [5700]
		STATE OF INCORPORATION:			NJ
		FISCAL YEAR END:			0201

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05998
		FILM NUMBER:		04533758

	BUSINESS ADDRESS:	
		STREET 1:		17 FIELD POINT DRIVE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		2014811100

	MAIL ADDRESS:	
		STREET 1:		1 CAPE MAY ST
		STREET 2:		1 CAPE MAY ST
		CITY:			HARRISON
		STATE:			NJ
		ZIP:			07029

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>0001071287</rptOwnerCik>
            <rptOwnerName>DAVIS CHARLES A /NJ/</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>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="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>102879.0274</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership
><natureOfOwnership><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>1423</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><value>47.915</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>101456.0274</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivat
iveTransaction><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>389.94</value><footnoteId id="F3"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1954.6944</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 U
NITS</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>28639</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>28639</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>131351</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNatu
re><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>RESTRICTED STOCK UNITS</value></securityTitle><conversionOrExercisePrice><footnoteId id="F5"/></conversionOrExercisePrice><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="F2"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F6"/></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle
><underlyingSecurityShares><value>3988</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>127363</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>2698.9403</value><footnoteId id="F4"/></transactionShares><transactionPricePerShare><footnoteId id="F6"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transac
tionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F6"/></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>COMMON</value></underlyingSecurityTitle><underlyingSecurityShares><value>2698.9403</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>16501.259</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 1,423 shares were withheld to cover applicable taxes.</footnote><footnote id="F2">Includes 71,900 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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</SEC-DOCUMENT>
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