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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,
 AaFMKgPmA+e9bnNFJ3qf5OaY1IuDN+inBf8V+ursksx19ElvPq8u+lZtfBdXKFYK
 40IQhgIqeqG48pf3SZmA9w==

<SEC-DOCUMENT>0000891092-05-000962.txt : 20050517
<SEC-HEADER>0000891092-05-000962.hdr.sgml : 20050517
<ACCEPTANCE-DATETIME>20050517143715
ACCESSION NUMBER:		0000891092-05-000962
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050516
FILED AS OF DATE:		20050517
DATE AS OF CHANGE:		20050517

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OMNICOM GROUP INC
		CENTRAL INDEX KEY:			0000029989
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ADVERTISING AGENCIES [7311]
		IRS NUMBER:				131514814
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		437 MADISON AVE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		2124153700

	MAIL ADDRESS:	
		STREET 1:		437 MADISON AVE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DOYLE DANE BERNBACH GROUP INC
		DATE OF NAME CHANGE:	19861117

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DOYLE DANE BERNBACH INTERNATIONAL INC
		DATE OF NAME CHANGE:	19850604

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DOYLE DANE BERNBACH INC
		DATE OF NAME CHANGE:	19781226

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			COOK ERROL M
		CENTRAL INDEX KEY:			0001142082
		STANDARD INDUSTRIAL CLASSIFICATION:	NEWSPAPERS:  PUBLISHING OR PUBLISHING & PRINTING [2711]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1226

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10551
		FILM NUMBER:		05838292

	BUSINESS ADDRESS:	
		STREET 1:		STATE STREET SQUARE
		STREET 2:		50 WEST STATE ST
		CITY:			TRENTON
		STATE:			NJ
		ZIP:			08605
		BUSINESS PHONE:		6093962200

	MAIL ADDRESS:	
		STREET 1:		STATE STREET SQUARE
		STREET 2:		50 WEST STATE STREET
		CITY:			TRENTON
		STATE:			NJ
		ZIP:			08605
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>e20904_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-05-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000029989</issuerCik>
        <issuerName>OMNICOM GROUP INC</issuerName>
        <issuerTradingSymbol>OMC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001142082</rptOwnerCik>
            <rptOwnerName>COOK ERROL M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OMNICOM GROUP INC.</rptOwnerStreet1>
            <rptOwnerStreet2>437 MADISON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, Par Value $0.15</value>
            </securityTitle>
            <transactionDate>
                <value>2005-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>82.54</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4716.32</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ Michael J. O'Brien, Attorney in Fact for Reporting Person</signatureName>
        <signatureDate>2005-05-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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