As filed with the Securities and Exchange Commission on March 17, 1999
                                                   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 PROFIT-SHARING RETIREMENT 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.
                              Dewey Ballantine LLP
                           1301 Avenue of the Americas
                            New York, New York 10019
                                 (212) 259-6570

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

<PAGE>

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
==============================================================================================
                                                           Proposed Maximum
     Title of                           Proposed Maximum       Aggregate          Amount of
  Securities to        Amount to be      Offering Price        Offering       Registration Fee
be Registered (1)       Registered        Per Share (2)        Price (2)             (2)
----------------------------------------------------------------------------------------------
<S>                     <C>                 <C>              <C>                 <C>       
 Common Stock of
 Omnicom Group
 Inc., par value
 $.50 per share .....   1,500,000           $70.21875        $105,328,125        $29,281.22
==============================================================================================
</TABLE>

(1)   In addition, pursuant to Rule 416(c) under the Securities Act of 1933, as
      amended (the "Securities Act"), this registration statement also covers an
      indeterminate amount of interests to be offered or sold pursuant to the
      employee benefit plan described herein.

(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 March 11, 1999.

<PAGE>

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

            The following documents have been filed by Omnicom Group Inc. (the
"Company") (File No. 1-10551) with the Securities and Exchange Commission (the
"Commission") and are incorporated herein by reference:

      (a)   the Company's Annual Report on Form 10-K for the fiscal year ended
            December 31, 1997;

      (b)   the Company's Quarterly Reports on Form 10-Q for the quarters ended
            March 31, 1998, June 30, 1998 and September 30, 1998;

      (c)   the Company's Current Reports on Form 8-K dated January 20, 1998,
            March 4, 1998 and March 6, 1998; and

      (d)   the description of the Company's Common Stock contained in the
            Registration Statement filed pursuant to Section 12 of the
            Securities Exchange Act of 1934, as amended (the "Exchange Act"),
            and any amendment or report filed for purposes of updating that
            description.

            All documents filed by the Company or the Omnicom Group
Profit-Sharing Retirement Plan (the "Plan") with the Commission pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to the date
of this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered have been sold or which
deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this Registration Statement and to be part hereof
from the date of filing of such documents. Any statement contained in any
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any other subsequently
filed document which also is or is deemed to be incorporated by reference herein
modifies or supersedes such statement. Any such statement so modified or
superseded shall not be deemed, except as modified or superseded, to constitute
a part of this Registration Statement.

            The consolidated financial statements and financial statement
schedules of the Company and its subsidiaries included in the Company's Annual
Report on Form 10-K for the fiscal year ended December 31, 1997 have been
incorporated herein by reference in reliance on the reports, also incorporated
herein by reference, of Arthur Andersen LLP, independent certified public
accountants, given on their authority as experts in auditing and accounting.


                                      II-1
<PAGE>

Item 4. Description of Securities.

            Not applicable.

Item 5. Interests of Named Experts and Counsel.

            Not applicable.

Item 6. Indemnification of Directors and Officers.

            The Company's Certificate of Incorporation contains a provision
limiting the liability of directors (except for approving statutorily prohibited
dividends, share repurchases or redemptions, distributions of assets on
dissolution or loans to directors) to acts or omissions in bad faith, involving
intentional misconduct or a knowing violation of the law, or resulting in
personal gain to which the director was not legally entitled. The Company's
By-Laws provide that an officer or director will be indemnified against any
costs or liabilities, including attorneys fees and amounts paid in settlement
with the consent of the Company in connection with any claim, action or
proceeding to the fullest extent permitted by the New York Business Corporation
Law.

            Section 722(a) of the New York Business Corporation Law provides
that a corporation may indemnify any officer or director made, or threatened to
be made, a party to an action other than one by or in the right of the
corporation, including an action by or in the right of any other corporation or
other enterprise which any director or officer of the corporation served in any
capacity at the request of the corporation, because he was a director or officer
of the corporation, or served such other corporation or other enterprise in any
capacity, against judgments, fines, amounts paid in settlement and reasonable
expenses, including attorney's fees actually and necessarily incurred as a
result of such action, or any appeal therein, if such director or officer acted,
in good faith, for a purpose which he reasonably believed to be in, or in the
case of service for any other corporation or other enterprise, not opposed to,
the best interests of the corporation and, in criminal actions, in addition, had
no reasonable cause to believe that his conduct was unlawful.

            Section 722(c) of the New York Business Corporation Law provides
that a corporation may indemnify any officer or director made, or threatened to
be made, a party to an action by or in the right of the corporation by reason of
the fact that he is or was an officer or director of the corporation, or is or
was serving at the request of the corporation as a director or officer of any
other corporation, or other enterprise, against amounts paid in settlement and
reasonable expenses, including attorneys' fees, actually and necessarily
incurred by him in connection with the defense or settlement of such action, or
in connection with an appeal therein, if such director or officer acted, in good
faith, for a purpose which he reasonably believed to be in, or, in the case of
service for another corporation or other enterprise, not opposed to, the best
interests of the corporation. The corporation may not, however, indemnify any
officer or director pursuant to Section 722(c) in respect of (1) a threatened
action, or a pending action which is settled or otherwise disposed of, or (2)
any claim, issue or matter as to which such 


                                      II-2
<PAGE>

person shall have been adjudged to be liable to the corporation, unless and only
to the extent that the court in which the action was brought or, if no action
was brought, any court of competent jurisdiction, determines in its discretion,
that the person is fairly and reasonably entitled to indemnity for such portion
of the settlement and expenses as the court deems proper.

            Section 723 of the New York Business Corporation Law provides that
an officer or director who has been successful on the merits or otherwise in the
defense of a civil or criminal action of the character set forth in Section 722
is entitled to indemnification as permitted in such section. Section 724 of the
New York Business Corporation Law permits a court to award the indemnification
required by Section 722.

            The Company has entered into agreements with its directors to
indemnify them for liabilities or costs arising out of any alleged or actual
breach of duty, neglect, errors or omissions while serving as a director. The
Company also maintains and pays premiums for directors' and officers' liability
insurance policies.

            Section 15.6 of the Plan provides that the duties, powers and
responsibilities reserved to the Administrative Committee appointed to
administer the Plan (the "Committee") may be allocated among the members (if
there be more than one), in which case, except as may be required by the
Employee Retirement Income Security Act of 1974, as amended (or any successor
statute) (the "Act"), no member of the Committee shall have any liability with
respect to any duties, powers or responsibilities not allocated to him, or for
the acts or omissions of any other member. Section 15.6 of the Plan provides
that the Company may indemnify, to the extent permitted by the Act, the members
of the Committee against all loss and/or expense arising out of their actions
and omissions in that capacity.

Item 7. Exemption from Registration Claimed.

            Not applicable.

Item 8. Exhibits.

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

     4.1         Omnicom Group Profit-Sharing Retirement Plan.

     4.2         Agreement and Declaration of Trust.

     5           Opinion and Consent of Dewey Ballantine LLP.

    23.1         Consent of Dewey Ballantine LLP (included in Exhibit 5 hereto).

    23.2         Consent of Arthur Andersen LLP.

    24           Power of Attorney (included on Signature Page).


                                      II-3
<PAGE>

            The Company has caused or will cause the Plan and any amendment
thereto to be submitted to the Internal Revenue Service ("IRS") in a timely
manner and has caused or will cause to be made all changes required by the IRS
in order to qualify such plan.

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.

      (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
Registration Statement shall be deemed to be a new registration statement
relating to the securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.


                                      II-4
<PAGE>

      (c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.


                                      II-5
<PAGE>

                                   SIGNATURES

            The Registrant. 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 March 17, 1999.

                                        OMNICOM GROUP INC.


                                        By: /s/ John Wren
                                            ------------------------------------
                                            John 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 John Wren and Barry J. Wagner, and each
of them, with full powers of substitution, his or her 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-in-fact 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 and interests registered
pursuant hereto, including specifically, but without limitation thereof, power
and authority to sign his or her name, in any and all capacities set forth
beneath his or her name, to any amendment to this Registration Statement in
respect of said shares and interests 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-in-fact and agents shall
do or cause to be done by virtue hereof.

Date: March 17, 1999                   By: /s/ John Wren                       
                                           -------------------------------------
                                           John Wren                           
                                           Chief Executive Officer and Director
                                           (Principal Executive Officer)       
                                                                               

Date: March 17, 1999                   By: /s/ Randall Weisenburger            
                                           -------------------------------------
                                           Randall Weisenburger                
                                           Chief Financial Officer             
                                           (Principal Financial Officer)       
<PAGE>

Date: March 17, 1999                   By: /s/ Philip J. Angelastro            
                                           -------------------------------------
                                           Philip J. Angelastro                
                                           Controller                          
                                           (Principal Accounting Officer)      


Date: March 17, 1999                   By: /s/ Bernard Brochand                
                                           -------------------------------------
                                           Bernard Brochand                    
                                           Director                            


Date: March 17, 1999                   By: /s/ Robert J. Callander             
                                           -------------------------------------
                                           Robert J. Callander                 
                                           Director                            


Date: March 17, 1999                   By: /s/ James A. Cannon        
                                           -------------------------------------
                                           James A. Cannon                     
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Leonard S. Coleman, Jr.         
                                           -------------------------------------
                                           Leonard S. Coleman, Jr.             
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Bruce Crawford                  
                                           -------------------------------------
                                           Bruce Crawford                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Susan S. Denison                
                                           -------------------------------------
                                           Susan S. Denison                    
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ John R. Murphy              
                                           -------------------------------------
                                           John R. Murphy                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ John R. Purcell                 
                                           -------------------------------------
                                           John R. Purcell                     
                                           Director                            
<PAGE>

Date: March 17, 1999                   By: /s/ Keith L. Reinhard               
                                           -------------------------------------
                                           Keith L. Reinhard                   
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Allen Rosenshine                
                                           -------------------------------------
                                           Allen Rosenshine                    
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Gary L. Roubos                  
                                           -------------------------------------
                                           Gary L. Roubos                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Quentin I. Smith, Jr.           
                                           -------------------------------------
                                           Quentin I. Smith, Jr.               
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Egon P.S. Zehnder              
                                           -------------------------------------
                                           Egon P.S. Zehnder                 
                                           Director                            
<PAGE>

            The Plan. Pursuant to the requirements of the Securities Act of
1933, the Administrative Committee for the Plan 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 March 17, 1999.

                                    OMNICOM GROUP PROFIT-SHARING RETIREMENT PLAN


                                    By: /s/ Leslie Chiocco
                                        ---------------------------------------
                                        Name: Leslie Chiocco
                                        Title: Authorized Signatory for the
                                                 Administrative Committee

<PAGE>

                                INDEX TO EXHIBITS

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

     4.1         Omnicom Group Profit-Sharing Retirement Plan.

     4.2         Agreement and Declaration of Trust.

     5           Opinion and Consent of Dewey Ballantine LLP.

    23.1         Consent of Dewey Ballantine LLP (included in Exhibit 5 hereto).

    23.2         Consent of Arthur Andersen LLP.

    24           Power of Attorney (included on Signature Page).
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 25731}]
{"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": "333-74591", "film-number": "99567394"}, "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 March 17, 1999
                                                   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 PROFIT-SHARING RETIREMENT 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.
                              Dewey Ballantine LLP
                           1301 Avenue of the Americas
                            New York, New York 10019
                                 (212) 259-6570

                                -----------------
CALCULATION OF REGISTRATION FEE
==============================================================================================
                                                           Proposed Maximum
     Title of                           Proposed Maximum       Aggregate          Amount of
  Securities to        Amount to be      Offering Price        Offering       Registration Fee
be Registered (1)       Registered        Per Share (2)        Price (2)             (2)
----------------------------------------------------------------------------------------------
Common Stock of
 Omnicom Group
 Inc., par value
 $.50 per share .....   1,500,000           $70.21875        $105,328,125        $29,281.22
==============================================================================================
(1)   In addition, pursuant to Rule 416(c) under the Securities Act of 1933, as
      amended (the "Securities Act"), this registration statement also covers an
      indeterminate amount of interests to be offered or sold pursuant to the
      employee benefit plan described herein.

(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 March 11, 1999.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

            The following documents have been filed by Omnicom Group Inc. (the
"Company") (File No. 1-10551) with the Securities and Exchange Commission (the
"Commission") and are incorporated herein by reference:

      (a)   the Company's Annual Report on Form 10-K for the fiscal year ended
            December 31, 1997;

      (b)   the Company's Quarterly Reports on Form 10-Q for the quarters ended
            March 31, 1998, June 30, 1998 and September 30, 1998;

      (c)   the Company's Current Reports on Form 8-K dated January 20, 1998,
            March 4, 1998 and March 6, 1998; and

      (d)   the description of the Company's Common Stock contained in the
            Registration Statement filed pursuant to Section 12 of the
            Securities Exchange Act of 1934, as amended (the "Exchange Act"),
            and any amendment or report filed for purposes of updating that
            description.

            All documents filed by the Company or the Omnicom Group
Profit-Sharing Retirement Plan (the "Plan") with the Commission pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to the date
of this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered have been sold or which
deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this Registration Statement and to be part hereof
from the date of filing of such documents. Any statement contained in any
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any other subsequently
filed document which also is or is deemed to be incorporated by reference herein
modifies or supersedes such statement. Any such statement so modified or
superseded shall not be deemed, except as modified or superseded, to constitute
a part of this Registration Statement.

            The consolidated financial statements and financial statement
schedules of the Company and its subsidiaries included in the Company's Annual
Report on Form 10-K for the fiscal year ended December 31, 1997 have been
incorporated herein by reference in reliance on the reports, also incorporated
herein by reference, of Arthur Andersen LLP, independent certified public
accountants, given on their authority as experts in auditing and accounting.

                                      II-1
Item 4. Description of Securities.

            Not applicable.

Item 5. Interests of Named Experts and Counsel.

            Not applicable.

Item 6. Indemnification of Directors and Officers.

            The Company's Certificate of Incorporation contains a provision
limiting the liability of directors (except for approving statutorily prohibited
dividends, share repurchases or redemptions, distributions of assets on
dissolution or loans to directors) to acts or omissions in bad faith, involving
intentional misconduct or a knowing violation of the law, or resulting in
personal gain to which the director was not legally entitled. The Company's
By-Laws provide that an officer or director will be indemnified against any
costs or liabilities, including attorneys fees and amounts paid in settlement
with the consent of the Company in connection with any claim, action or
proceeding to the fullest extent permitted by the New York Business Corporation
Law.

            Section 722(a) of the New York Business Corporation Law provides
that a corporation may indemnify any officer or director made, or threatened to
be made, a party to an action other than one by or in the right of the
corporation, including an action by or in the right of any other corporation or
other enterprise which any director or officer of the corporation served in any
capacity at the request of the corporation, because he was a director or officer
of the corporation, or served such other corporation or other enterprise in any
capacity, against judgments, fines, amounts paid in settlement and reasonable
expenses, including attorney's fees actually and necessarily incurred as a
result of such action, or any appeal therein, if such director or officer acted,
in good faith, for a purpose which he reasonably believed to be in, or in the
case of service for any other corporation or other enterprise, not opposed to,
the best interests of the corporation and, in criminal actions, in addition, had
no reasonable cause to believe that his conduct was unlawful.

            Section 722(c) of the New York Business Corporation Law provides
that a corporation may indemnify any officer or director made, or threatened to
be made, a party to an action by or in the right of the corporation by reason of
the fact that he is or was an officer or director of the corporation, or is or
was serving at the request of the corporation as a director or officer of any
other corporation, or other enterprise, against amounts paid in settlement and
reasonable expenses, including attorneys' fees, actually and necessarily
incurred by him in connection with the defense or settlement of such action, or
in connection with an appeal therein, if such director or officer acted, in good
faith, for a purpose which he reasonably believed to be in, or, in the case of
service for another corporation or other enterprise, not opposed to, the best
interests of the corporation. The corporation may not, however, indemnify any
officer or director pursuant to Section 722(c) in respect of (1) a threatened
action, or a pending action which is settled or otherwise disposed of, or (2)
any claim, issue or matter as to which such 

                                      II-2
person shall have been adjudged to be liable to the corporation, unless and only
to the extent that the court in which the action was brought or, if no action
was brought, any court of competent jurisdiction, determines in its discretion,
that the person is fairly and reasonably entitled to indemnity for such portion
of the settlement and expenses as the court deems proper.

            Section 723 of the New York Business Corporation Law provides that
an officer or director who has been successful on the merits or otherwise in the
defense of a civil or criminal action of the character set forth in Section 722
is entitled to indemnification as permitted in such section. Section 724 of the
New York Business Corporation Law permits a court to award the indemnification
required by Section 722.

            The Company has entered into agreements with its directors to
indemnify them for liabilities or costs arising out of any alleged or actual
breach of duty, neglect, errors or omissions while serving as a director. The
Company also maintains and pays premiums for directors' and officers' liability
insurance policies.

            Section 15.6 of the Plan provides that the duties, powers and
responsibilities reserved to the Administrative Committee appointed to
administer the Plan (the "Committee") may be allocated among the members (if
there be more than one), in which case, except as may be required by the
Employee Retirement Income Security Act of 1974, as amended (or any successor
statute) (the "Act"), no member of the Committee shall have any liability with
respect to any duties, powers or responsibilities not allocated to him, or for
the acts or omissions of any other member. Section 15.6 of the Plan provides
that the Company may indemnify, to the extent permitted by the Act, the members
of the Committee against all loss and/or expense arising out of their actions
and omissions in that capacity.

Item 7. Exemption from Registration Claimed.

            Not applicable.

Item 8. Exhibits.

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

     4.1         Omnicom Group Profit-Sharing Retirement Plan.

     4.2         Agreement and Declaration of Trust.

     5           Opinion and Consent of Dewey Ballantine LLP.

    23.1         Consent of Dewey Ballantine LLP (included in Exhibit 5 hereto).

    23.2         Consent of Arthur Andersen LLP.

    24           Power of Attorney (included on Signature Page).

                                      II-3
The Company has caused or will cause the Plan and any amendment
thereto to be submitted to the Internal Revenue Service ("IRS") in a timely
manner and has caused or will cause to be made all changes required by the IRS
in order to qualify such plan.

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.

      (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in this
Registration Statement shall be deemed to be a new registration statement
relating to the securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

                                      II-4
(c) Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the registrant pursuant to the foregoing provisions, or otherwise,
the registrant has been advised that in the opinion of the Securities and
Exchange Commission such indemnification is against public policy as expressed
in the Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.

                                      II-5
SIGNATURES

            The Registrant. 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 March 17, 1999.

                                        OMNICOM GROUP INC.

                                        By: /s/ John Wren
                                            ------------------------------------
                                            John 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 John Wren and Barry J. Wagner, and each
of them, with full powers of substitution, his or her 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-in-fact 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 and interests registered
pursuant hereto, including specifically, but without limitation thereof, power
and authority to sign his or her name, in any and all capacities set forth
beneath his or her name, to any amendment to this Registration Statement in
respect of said shares and interests 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-in-fact and agents shall
do or cause to be done by virtue hereof.

Date: March 17, 1999                   By: /s/ John Wren                       
                                           -------------------------------------
                                           John Wren                           
                                           Chief Executive Officer and Director
                                           (Principal Executive Officer)       
                                                                               

Date: March 17, 1999                   By: /s/ Randall Weisenburger            
                                           -------------------------------------
                                           Randall Weisenburger                
                                           Chief Financial Officer             
                                           (Principal Financial Officer)
Date: March 17, 1999                   By: /s/ Philip J. Angelastro            
                                           -------------------------------------
                                           Philip J. Angelastro                
                                           Controller                          
                                           (Principal Accounting Officer)      

Date: March 17, 1999                   By: /s/ Bernard Brochand                
                                           -------------------------------------
                                           Bernard Brochand                    
                                           Director                            

Date: March 17, 1999                   By: /s/ Robert J. Callander             
                                           -------------------------------------
                                           Robert J. Callander                 
                                           Director                            

Date: March 17, 1999                   By: /s/ James A. Cannon        
                                           -------------------------------------
                                           James A. Cannon                     
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Leonard S. Coleman, Jr.         
                                           -------------------------------------
                                           Leonard S. Coleman, Jr.             
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Bruce Crawford                  
                                           -------------------------------------
                                           Bruce Crawford                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Susan S. Denison                
                                           -------------------------------------
                                           Susan S. Denison                    
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ John R. Murphy              
                                           -------------------------------------
                                           John R. Murphy                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ John R. Purcell                 
                                           -------------------------------------
                                           John R. Purcell                     
                                           Director
Date: March 17, 1999                   By: /s/ Keith L. Reinhard               
                                           -------------------------------------
                                           Keith L. Reinhard                   
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Allen Rosenshine                
                                           -------------------------------------
                                           Allen Rosenshine                    
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Gary L. Roubos                  
                                           -------------------------------------
                                           Gary L. Roubos                      
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Quentin I. Smith, Jr.           
                                           -------------------------------------
                                           Quentin I. Smith, Jr.               
                                           Director                            
                                                                               

Date: March 17, 1999                   By: /s/ Egon P.S. Zehnder              
                                           -------------------------------------
                                           Egon P.S. Zehnder                 
                                           Director
The Plan. Pursuant to the requirements of the Securities Act of
1933, the Administrative Committee for the Plan 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 March 17, 1999.

                                    OMNICOM GROUP PROFIT-SHARING RETIREMENT PLAN

                                    By: /s/ Leslie Chiocco
                                        ---------------------------------------
                                        Name: Leslie Chiocco
                                        Title: Authorized Signatory for the
                                                 Administrative Committee
INDEX TO EXHIBITS

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

     4.1         Omnicom Group Profit-Sharing Retirement Plan.

     4.2         Agreement and Declaration of Trust.

     5           Opinion and Consent of Dewey Ballantine LLP.

    23.1         Consent of Dewey Ballantine LLP (included in Exhibit 5 hereto).

    23.2         Consent of Arthur Andersen LLP.

    24           Power of Attorney (included on Signature Page).