Exhibit 24

                              OMNICOM GROUP INC.
                       REGISTRATION STATEMENT ON FORM S-8
                                POWER OF ATTORNEY

      The undersigned officer and/or director of Omnicom Group Inc., a New York
corporation (the "Registrant"), does hereby make, constitute and appoint each of
John D. Wren and Michael J. O'Brien, with full power of substitution and
resubstitution, as attorney of the undersigned, to execute and file (i) a
Registration Statement on Form S-8 (the "Form S-8 Registration Statement") with
respect to the registration under the Securities Act, of shares of Common Stock
of the Registrant issuable in connection with the Registrant's Omnicom Group
Inc. Director Equity Plan, (ii) any and all amendments, including post-effective
amendments, and exhibits to the Form S-8 Registration Statement and (iii) any
and all applications or other documents to be filed with the Securities and
Exchange Commission or any state securities commission or other regulatory
authority with respect to the securities covered by the Form S-8 Registration
Statement, with full power and authority to do and perform any and all acts and
things whatsoever necessary, appropriate or desirable to be done in the
premises, or in the name, place and stead of the said director and/or officer,
hereby ratifying and approving the acts of said attorneys and any of them and
any such substitute.

      IN WITNESS WHEREOF, the undersigned have subscribed these presents as of
the 24th day of May, 2004.

Signature                        Title
- ---------                        -----

   /s/ John D. Wren
- ----------------------------     President, Chief Executive Officer and Director
       John D. Wren

/s/ Randall J. Weisenburger
- ----------------------------     Executive Vice President and Chief Financial
    Randall J. Weisenburger      Officer

/s/ Philip J. Angelastro
- ----------------------------     Senior Vice President of Finance and Controller
    Philip J. Angelastro

/s/ Robert Charles Clark
- ----------------------------     Director
    Robert Charles Clark

/s/ Leonard S. Coleman, Jr.
- ----------------------------     Director
    Leonard S. Coleman, Jr.

  /s/ Errol M. Cook
- ----------------------------     Director
      Errol M. Cook




  /s/ Bruce Crawford
- ----------------------------     Director
      Bruce Crawford

 /s/ Susan S. Denison
- ----------------------------     Director
     Susan S. Denison

/s/ Michael A. Henning
- ----------------------------     Director
    Michael A. Henning

  /s/ John R. Murphy
- ----------------------------     Director
      John R. Murphy

  /s/ John R. Purcell
- ----------------------------     Director
      John R. Purcell

/s/ Linda Johnson Rice
- ----------------------------     Director
    Linda Johnson Rice

  /s/ Gary L. Roubos
- ----------------------------     Director
      Gary L. Roubos


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