================================================================================
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                   ----------

                                    FORM 8-K

                                   ----------

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

       Date of report (Date of earliest event reported): November 10, 2004

                                   ----------

                               OMNICOM GROUP INC.
               (Exact Name of Registrant as Specified in Charter)

                                   ----------

          New York                      1-10551                   13-1514814
(State or Other Jurisdiction          (Commission               (IRS Employer
      of Incorporation)               File Number)           Identification No.)

          437 Madison Avenue, New York, NY                          10022
      (Address of Principal Executive Offices)                    (Zip Code)

       Registrants' telephone number, including area code: (212) 415-3600

                                 Not Applicable
          (Former Name or Former Address, if Changed Since Last Report)

                                   ----------

      Check the appropriate box if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2.):

      |_|   Written communications pursuant to Rule 425 under Securities Act (17
            CFR 230.425)

      |_|   Soliciting material pursuant to Rule 14a-12 under Securities Act (17
            CFR 240.14a-12)

      |_|   Pre-commencement communications pursuant to Rule 14(d)-2(b) under
            the Exchange Act (17 CFR 240.14d-2(b))

      |_|   Pre-commencement communications pursuant to Rule 13(c) under the
            Exchange Act

================================================================================




================================================================================

Item 1.01 Entry into a Material Definitive Agreement.

      In connection with the expiration, on November 4, 2004, of the consent
solicitation commenced on October 21, 2004 by Omnicom Group Inc. ("OGI"),
Omnicom Capital Inc. ("OCI") and Omnicom Finance Inc. ("OFI" and together with
OGI and OCI, the "Issuers") to attain consents to amend the indenture under
which the Issuers' Zero Coupon Zero Yield Convertible Notes due 2033 (the
"Notes") were issued (the "Indenture"), the Issuers and JPMorgan Chase Bank (the
"Trustee") entered into the Third Supplemental Indenture (the "Third
Supplemental Indenture"), dated as of November 10, 2004, among the Issuers and
the Trustee, which is binding on all holders of the Notes that consented to the
amendments during the consent solicitation ("Consenting Noteholders"). Pursuant
to the Third Supplemental Indenture, the Issuers agree (i) to surrender their
right to pay Consenting Noteholders who are converting their Notes pursuant to
Article 10 of the Indenture with shares of common stock of OGI and (ii) to
surrender their right to designate a financial institution to deliver shares of
common stock of OGI upon conversion pursuant to Article 10 of the Indenture.

      The description of the Third Supplemental Indenture is not complete and is
qualified in its entirety by the full text of such document, which is Exhibit
4.1 hereto and incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits.

      (c)   Exhibits.

Exhibit
Number      Description
-------     --------------------------------------------------------------------

4.1         Third Supplemental Indenture, dated November 10, 2004, among Omnicom
            Group Inc., Omnicom Capital Inc., Omnicom Finance Inc. and JPMorgan
            Chase Bank




================================================================================

                                   SIGNATURES

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                         OMNICOM GROUP INC.

                                         By: /s/ PHILIP J. ANGELASTRO
                                             Name:  Philip J. Angelastro
                                             Title: Senior Vice President and
                                                    Controller

Date: November 16, 2004


                                       2


================================================================================

                                  EXHIBIT INDEX

Exhibit
Number      Description
-------     --------------------------------------------------------------------

4.1         Third Supplemental Indenture, dated November 10, 2004, among Omnicom
            Group Inc., Omnicom Capital Inc., Omnicom Finance Inc. and JPMorgan
            Chase Bank


                                       3