As filed  with the  Securities  and  Exchange  Commission  on  December  8, 1997
                                               Registration Number 333-_________

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                            -----------------------

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                            -----------------------

                               OMNICOM GROUP INC.
             (Exact name of registrant as specified in its charter)

                   New York                                  13-1514814
         (State or other jurisdiction                     (I.R.S. Employer
       of incorporation or organization)               Identification Number)

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

                       OMNICOM GROUP INC. 1987 STOCK PLAN
                            (Full title of the plan)

                              Barry J. Wagner, Esq.
                          Secretary and General Counsel
                               Omnicom Group Inc.
                               437 Madison Avenue
                            New York, New York 10022
                                 (212) 415-3600
                      (Name, address and telephone number,
                   including area code, of agent for service)

                            -----------------------

                                   Copies to:
                              Linda E. Ransom, Esq.
                       Donovan Leisure Newton & Irvine LLP
                              30 Rockefeller Plaza
                            New York, New York 10112
                                 (212) 632-3350

                            -----------------------

<PAGE>


                         CALCULATION OF REGISTRATION FEE

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

                                                   Proposed
   Title of                        Proposed         Maximum
 Securities to   Amount to be       Maximum        Aggregate       Amount of
 be Registered  Registered (1)  Offering Price     Offering      Registration
                                 Per Share (2)     Price (2)        Fee (2)

--------------------------------------------------------------------------------

Common Stock of
Omnicom Group
Inc., par value
$.50 per share      3,600,000       $73.6875     $265,275,000      $78,256.13

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


(1)  Represents  shares of Common Stock  issuable  pursuant to the Omnicom Group
     Inc. 1987 Stock Plan (the "1987 Stock Plan") being  registered  hereon.  In
     addition,  shares of Common Stock issuable  pursuant to the 1987 Stock Plan
     previously have been registered with the Securities and Exchange Commission
     as follows:  3,000,000  shares  registered on June 16, 1989 on Registration
     Statement No. 33-29375,  3,500,000 shares registered on October 19, 1990 on
     Registration  Statement No. 33-37380,  and 3,000,000  shares  registered on
     December 16, 1993 on  Registration  Statement No.  33-51493.  In accordance
     with Rule 416(b), the foregoing share amounts have been adjusted to reflect
     Omnicom Group Inc.'s  two-for-one  stock split in the form of a one hundred
     percent  dividend  on the  registrant's  outstanding  Common  Stock paid to
     shareholders of record on December 15, 1995. Also,  pursuant to Rule 416(a)
     and Rule 416(b),  this  Registration  Statement and Registration  Statement
     Nos.  33-29375,  33-37380,  and  33-51493  shall be deemed to include  upon
     issuance shares issuable pursuant to Omnicom Group Inc.'s two-for-one stock
     split in the form of a one hundred  percent  dividend  on the  registrant's
     outstanding  Common Stock payable to shareholders of record on December 16,
     1997.

(2)  Estimated for the sole purpose of computing the registration  fee. Pursuant
     to Securities Act Rules 457(c) and (h), the proposed maximum offering price
     per share is calculated as the average of the high and low prices, reported
     by the New York Stock Exchange, Inc., of the common stock of the registrant
     as of December 5, 1997.


<PAGE>


                INCORPORATION OF EARLIER REGISTRATION STATEMENTS

          The contents of Registration Statement No. 33-29375 and Post-Effective
Amendment No. 1 thereto,  Registration  Statement No. 33-37380, and Registration
Statement No. 33-51493 are incorporated herein by reference.

          The validity of the shares of Common Stock,  par value $.50 per share,
of Omnicom  Group Inc.  to be issued  hereunder  will be passed upon for Omnicom
Group Inc. by Donovan  Leisure  Newton & Irvine LLP, 30 Rockefeller  Plaza,  New
York, New York 10112.

Item 8.   Exhibits.

     EXHIBIT NUMBER                     DESCRIPTION
     --------------                     -----------

          5          Opinion and Consent of Donovan Leisure Newton & Irvine LLP.

         23.1        Consent of Donovan Leisure Newton & Irvine LLP (included in
                     Exhibit 5 hereto).

         23.2        Consent of Arthur Andersen LLP.

Item 9.  Undertakings.

     (a)  The undersigned registrant hereby undertakes:

          (1) To file,  during  any  period  in which  offers or sales are being
made, a post-effective amendment to this Registration Statement:

               (i) to include any prospectus  required by Section  10(a)(3)
     of the Securities Act of 1933;

               (ii) to  reflect  in the  prospectus  any  facts or events
     arising after the effective date of the  Registration  Statement (or the
     most recent post-effective amendment thereof) which,  individually or in
     the aggregate,  represent a fundamental  change in the  information  set
     forth in the Registration Statement; and

               (iii) to include any material  information with respect to
     the plan of distribution  not previously  disclosed in the  Registration
     Statement or any material change to such information in the Registration
     Statement;

PROVIDED,  HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
information  required  to be  included in a  post-effective  amendment  by those
paragraphs  is  contained  in periodic  reports  filed with or  furnished to the
Commission  by the  registrant  pursuant  to Section 13 or Section  15(d) of the
Securities  Exchange  Act of 1934  that are  incorporated  by  reference  in the
Registration Statement.

          (2) That,  for the  purpose of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.


<PAGE>

                                   SIGNATURES

               Pursuant to the  requirements  of the  Securities Act of 1933, as
amended, the registrant certifies that it has reasonable grounds to believe that
it meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in the City of New York,  State of New York,  on  December 8,
1997.

                                        OMNICOM GROUP INC.


                                        By: /S/ JOHN D. WREN
                                            ------------------------------------
                                            John D. Wren
                                            Chief Executive Officer and Director

               Pursuant to the  requirements  of the  Securities Act of 1933, as
amended, this Registration Statement has been signed by the following persons in
the capacities and on the date indicated.  Each person whose  signature  appears
below does  hereby  constitute  and  appoint  Jonathan  E.  Ramsden and Barry J.
Wagner, and each of them, with full powers of substitution,  his true and lawful
attorneys-in-fact  and  agents to do any and all acts and  things and to execute
any and all  instruments  which said  attorneys and agents may deem necessary or
advisable to enable the registrant to comply with the Securities Act of 1933, as
amended,  and any rules,  regulations  and  requirements  of the  Securities and
Exchange  Commission in respect  thereof,  in connection  with the  registration
under said Act of shares of Common Stock registered  pursuant hereto,  including
specifically,  but without limitation  thereof,  power and authority to sign his
name, in any and all  capacities set forth beneath his name, to any amendment to
this Registration Statement in respect of said shares and to any documents filed
as part of or in connection with said Registration Statement or amendments;  and
the  undersigned  does hereby  ratify and confirm  all that said  attorneys  and
agents shall do or cause to be done by virtue hereof.

Date:  December 8, 1997                 By: /S/ JOHN D. WREN
                                            ------------------------------------
                                            John D. Wren
                                            Chief Executive Officer and Director
                                            (Principal Executive Officer)


Date:  December 8, 1997                 By: /S/ FRED J. MEYER
                                            ------------------------------------
                                            Fred J. Meyer
                                            Chief Financial Officer
                                            (Principal Financial Officer)


Date:  December 8, 1997                 By: /S/ JONATHAN E. RAMSDEN
                                            ------------------------------------
                                            Jonathan E. Ramsden
                                            Controller
                                            (Principal Accounting Officer)


Date:  December 8, 1997                 By: /S/ BERNARD BROCHAND
                                            ------------------------------------
                                            Bernard Brochand
                                            Director


Date:  December 8, 1997                 By: /S/ ROBERT J. CALLANDER
                                            ------------------------------------
                                            Robert J. Callander
                                            Director


Date:  December 8, 1997                 By: /S/ JAMES A. CANNON
                                            ------------------------------------
                                            James A. Cannon
                                            Director


Date:  December 8, 1997                 By: /S/ LEONARD S. COLEMAN, JR.
                                            ------------------------------------
                                            Leonard S. Coleman, Jr.
                                            Director


Date:  December 8, 1997                 By: /S/ BRUCE CRAWFORD
                                            ------------------------------------
                                            Bruce Crawford
                                            Director


Date:  December 8, 1997                 By: /S/ SUSAN S. DENISON
                                            ------------------------------------
                                            Susan S. Denison
                                            Director


Date:  December 8, 1997                 By: /S/ JOHN R. MURPHY
                                            ------------------------------------
                                            John R. Murphy
                                            Director


Date:  December 8, 1997                 By: /S/ JOHN R. PURCELL
                                            ------------------------------------
                                            John R. Purcell
                                            Director


Date:  December 8, 1997                 By: /S/ KEITH L. REINHARD
                                            ------------------------------------
                                            Keith L. Reinhard
                                            Director


Date:  December 8, 1997                 By: /S/ ALLEN ROSENSHINE
                                            ------------------------------------
                                            Allen Rosenshine
                                            Director


Date:  December 8, 1997                 By: /S/ GARY L. ROUBOS
                                            ------------------------------------
                                            Gary L. Roubos
                                            Director


Date:  December 8, 1997                 By: /S/ QUENTIN I. SMITH, JR.
                                            ------------------------------------
                                            Quentin I. Smith, Jr.
                                            Director


Date:  December 8, 1997                 By: /S/ WILLIAM G. TRAGOS
                                            ------------------------------------
                                            William G. Tragos
                                            Director


Date:  December 8, 1997                 By: /S/ EGON P. S. ZEHNDER
                                            ------------------------------------
                                            Egon P. S. Zehnder
                                            Director


<PAGE>


                                INDEX TO EXHIBITS

     EXHIBIT NUMBER                     DESCRIPTION
     --------------                     -----------

          5          Opinion and Consent of Donovan Leisure Newton & Irvine LLP.

         23.1        Consent of Donovan Leisure Newton & Irvine LLP (included in
                     Exhibit 5 hereto).

         23.2        Consent of Arthur Andersen LLP.
[{"type": "S-8", "sequence": "1", "description": "REGISTRATION STATEMENT", "secsgml_size_bytes": 14674}]
{"company-data": {"conformed-name": "OMNICOM GROUP INC", "cik": "0000029989", "assigned-sic": "7311", "irs-number": "131514814", "state-of-incorporation": "NY", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-41717", "film-number": "97733980"}, "business-address": {"street1": "437 MADISON AVE", "city": "NEW YORK", "state": "NY", "zip": "10022", "phone": "2124153700"}, "mail-address": {"street1": "437 MADISON AVE", "city": "NEW YORK", "state": "NY", "zip": "10022"}, "former-company": [{"former-conformed-name": "DOYLE DANE BERNBACH GROUP INC", "date-changed": "19861117"}, {"former-conformed-name": "DOYLE DANE BERNBACH INTERNATIONAL INC", "date-changed": "19850604"}, {"former-conformed-name": "DOYLE DANE BERNBACH INC", "date-changed": "19781226"}]}
As filed  with the  Securities  and  Exchange  Commission  on  December  8, 1997
                                               Registration Number 333-_________

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                            -----------------------

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                            -----------------------

                               OMNICOM GROUP INC.
             (Exact name of registrant as specified in its charter)

                   New York                                  13-1514814
         (State or other jurisdiction                     (I.R.S. Employer
       of incorporation or organization)               Identification Number)

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

                       OMNICOM GROUP INC. 1987 STOCK PLAN
                            (Full title of the plan)

                              Barry J. Wagner, Esq.
                          Secretary and General Counsel
                               Omnicom Group Inc.
                               437 Madison Avenue
                            New York, New York 10022
                                 (212) 415-3600
                      (Name, address and telephone number,
                   including area code, of agent for service)

                            -----------------------

                                   Copies to:
                              Linda E. Ransom, Esq.
                       Donovan Leisure Newton & Irvine LLP
                              30 Rockefeller Plaza
                            New York, New York 10112
                                 (212) 632-3350

                            -----------------------
CALCULATION OF REGISTRATION FEE

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

                                                   Proposed
   Title of                        Proposed         Maximum
 Securities to   Amount to be       Maximum        Aggregate       Amount of
 be Registered  Registered (1)  Offering Price     Offering      Registration
                                 Per Share (2)     Price (2)        Fee (2)

--------------------------------------------------------------------------------

Common Stock of
Omnicom Group
Inc., par value
$.50 per share      3,600,000       $73.6875     $265,275,000      $78,256.13

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

(1)  Represents  shares of Common Stock  issuable  pursuant to the Omnicom Group
     Inc. 1987 Stock Plan (the "1987 Stock Plan") being  registered  hereon.  In
     addition,  shares of Common Stock issuable  pursuant to the 1987 Stock Plan
     previously have been registered with the Securities and Exchange Commission
     as follows:  3,000,000  shares  registered on June 16, 1989 on Registration
     Statement No. 33-29375,  3,500,000 shares registered on October 19, 1990 on
     Registration  Statement No. 33-37380,  and 3,000,000  shares  registered on
     December 16, 1993 on  Registration  Statement No.  33-51493.  In accordance
     with Rule 416(b), the foregoing share amounts have been adjusted to reflect
     Omnicom Group Inc.'s  two-for-one  stock split in the form of a one hundred
     percent  dividend  on the  registrant's  outstanding  Common  Stock paid to
     shareholders of record on December 15, 1995. Also,  pursuant to Rule 416(a)
     and Rule 416(b),  this  Registration  Statement and Registration  Statement
     Nos.  33-29375,  33-37380,  and  33-51493  shall be deemed to include  upon
     issuance shares issuable pursuant to Omnicom Group Inc.'s two-for-one stock
     split in the form of a one hundred  percent  dividend  on the  registrant's
     outstanding  Common Stock payable to shareholders of record on December 16,
     1997.

(2)  Estimated for the sole purpose of computing the registration  fee. Pursuant
     to Securities Act Rules 457(c) and (h), the proposed maximum offering price
     per share is calculated as the average of the high and low prices, reported
     by the New York Stock Exchange, Inc., of the common stock of the registrant
     as of December 5, 1997.
INCORPORATION OF EARLIER REGISTRATION STATEMENTS

          The contents of Registration Statement No. 33-29375 and Post-Effective
Amendment No. 1 thereto,  Registration  Statement No. 33-37380, and Registration
Statement No. 33-51493 are incorporated herein by reference.

          The validity of the shares of Common Stock,  par value $.50 per share,
of Omnicom  Group Inc.  to be issued  hereunder  will be passed upon for Omnicom
Group Inc. by Donovan  Leisure  Newton & Irvine LLP, 30 Rockefeller  Plaza,  New
York, New York 10112.

Item 8.   Exhibits.

     EXHIBIT NUMBER                     DESCRIPTION
     --------------                     -----------

          5          Opinion and Consent of Donovan Leisure Newton & Irvine LLP.

         23.1        Consent of Donovan Leisure Newton & Irvine LLP (included in
                     Exhibit 5 hereto).

         23.2        Consent of Arthur Andersen LLP.

Item 9.  Undertakings.

     (a)  The undersigned registrant hereby undertakes:

          (1) To file,  during  any  period  in which  offers or sales are being
made, a post-effective amendment to this Registration Statement:

               (i) to include any prospectus  required by Section  10(a)(3)
     of the Securities Act of 1933;

               (ii) to  reflect  in the  prospectus  any  facts or events
     arising after the effective date of the  Registration  Statement (or the
     most recent post-effective amendment thereof) which,  individually or in
     the aggregate,  represent a fundamental  change in the  information  set
     forth in the Registration Statement; and

               (iii) to include any material  information with respect to
     the plan of distribution  not previously  disclosed in the  Registration
     Statement or any material change to such information in the Registration
     Statement;

PROVIDED,  HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
information  required  to be  included in a  post-effective  amendment  by those
paragraphs  is  contained  in periodic  reports  filed with or  furnished to the
Commission  by the  registrant  pursuant  to Section 13 or Section  15(d) of the
Securities  Exchange  Act of 1934  that are  incorporated  by  reference  in the
Registration Statement.

          (2) That,  for the  purpose of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.
SIGNATURES

               Pursuant to the  requirements  of the  Securities Act of 1933, as
amended, the registrant certifies that it has reasonable grounds to believe that
it meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in the City of New York,  State of New York,  on  December 8,
1997.

                                        OMNICOM GROUP INC.

                                        By: /S/ JOHN D. WREN
                                            ------------------------------------
                                            John D. Wren
                                            Chief Executive Officer and Director

               Pursuant to the  requirements  of the  Securities Act of 1933, as
amended, this Registration Statement has been signed by the following persons in
the capacities and on the date indicated.  Each person whose  signature  appears
below does  hereby  constitute  and  appoint  Jonathan  E.  Ramsden and Barry J.
Wagner, and each of them, with full powers of substitution,  his true and lawful
attorneys-in-fact  and  agents to do any and all acts and  things and to execute
any and all  instruments  which said  attorneys and agents may deem necessary or
advisable to enable the registrant to comply with the Securities Act of 1933, as
amended,  and any rules,  regulations  and  requirements  of the  Securities and
Exchange  Commission in respect  thereof,  in connection  with the  registration
under said Act of shares of Common Stock registered  pursuant hereto,  including
specifically,  but without limitation  thereof,  power and authority to sign his
name, in any and all  capacities set forth beneath his name, to any amendment to
this Registration Statement in respect of said shares and to any documents filed
as part of or in connection with said Registration Statement or amendments;  and
the  undersigned  does hereby  ratify and confirm  all that said  attorneys  and
agents shall do or cause to be done by virtue hereof.

Date:  December 8, 1997                 By: /S/ JOHN D. WREN
                                            ------------------------------------
                                            John D. Wren
                                            Chief Executive Officer and Director
                                            (Principal Executive Officer)

Date:  December 8, 1997                 By: /S/ FRED J. MEYER
                                            ------------------------------------
                                            Fred J. Meyer
                                            Chief Financial Officer
                                            (Principal Financial Officer)

Date:  December 8, 1997                 By: /S/ JONATHAN E. RAMSDEN
                                            ------------------------------------
                                            Jonathan E. Ramsden
                                            Controller
                                            (Principal Accounting Officer)

Date:  December 8, 1997                 By: /S/ BERNARD BROCHAND
                                            ------------------------------------
                                            Bernard Brochand
                                            Director

Date:  December 8, 1997                 By: /S/ ROBERT J. CALLANDER
                                            ------------------------------------
                                            Robert J. Callander
                                            Director

Date:  December 8, 1997                 By: /S/ JAMES A. CANNON
                                            ------------------------------------
                                            James A. Cannon
                                            Director

Date:  December 8, 1997                 By: /S/ LEONARD S. COLEMAN, JR.
                                            ------------------------------------
                                            Leonard S. Coleman, Jr.
                                            Director

Date:  December 8, 1997                 By: /S/ BRUCE CRAWFORD
                                            ------------------------------------
                                            Bruce Crawford
                                            Director

Date:  December 8, 1997                 By: /S/ SUSAN S. DENISON
                                            ------------------------------------
                                            Susan S. Denison
                                            Director

Date:  December 8, 1997                 By: /S/ JOHN R. MURPHY
                                            ------------------------------------
                                            John R. Murphy
                                            Director

Date:  December 8, 1997                 By: /S/ JOHN R. PURCELL
                                            ------------------------------------
                                            John R. Purcell
                                            Director

Date:  December 8, 1997                 By: /S/ KEITH L. REINHARD
                                            ------------------------------------
                                            Keith L. Reinhard
                                            Director

Date:  December 8, 1997                 By: /S/ ALLEN ROSENSHINE
                                            ------------------------------------
                                            Allen Rosenshine
                                            Director

Date:  December 8, 1997                 By: /S/ GARY L. ROUBOS
                                            ------------------------------------
                                            Gary L. Roubos
                                            Director

Date:  December 8, 1997                 By: /S/ QUENTIN I. SMITH, JR.
                                            ------------------------------------
                                            Quentin I. Smith, Jr.
                                            Director

Date:  December 8, 1997                 By: /S/ WILLIAM G. TRAGOS
                                            ------------------------------------
                                            William G. Tragos
                                            Director

Date:  December 8, 1997                 By: /S/ EGON P. S. ZEHNDER
                                            ------------------------------------
                                            Egon P. S. Zehnder
                                            Director
INDEX TO EXHIBITS

     EXHIBIT NUMBER                     DESCRIPTION
     --------------                     -----------

          5          Opinion and Consent of Donovan Leisure Newton & Irvine LLP.

         23.1        Consent of Donovan Leisure Newton & Irvine LLP (included in
                     Exhibit 5 hereto).

         23.2        Consent of Arthur Andersen LLP.