As filed with the Securities and Exchange Commission on April 8, 2003.
                                                           Registration No. 333-
================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM S-3
                          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 of                               (I.R.S. Employer
incorporation or organization)                               Identification No.)

                               437 Madison Avenue
                               New York, NY 10022
                                 (212) 415-3600

       (Address, including zip code, and telephone number, including area
               code, of registrant's principal executive offices)

                              BARRY J. WAGNER, ESQ.
                          Secretary and General Counsel
                               Omnicom Group Inc.
                               437 Madison Avenue
                            New York, New York l0022
                                 (212) 415-3600
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                    Copy to:
                            MICHAEL D. DITZIAN, ESQ.
                               Davis & Gilbert LLP
                                  1740 Broadway
                            New York, New York 10019
                                 (212) 468-4800

                                   ----------

Approximate  date of commencement  of proposed sale to the public:  From time to
time after this Registration Statement becomes effective.

If the only securities  being registered on this Form are being offered pursuant
to dividend or interest reinvestment plans, please check the following box |_|

If any of the  securities  being  registered on this Form are to be offered on a
delayed or continuous  basis  pursuant to Rule 415 under the  Securities  Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, check the following box. |X|

If this Form is filed to register additional securities for an offering pursuant
to Rule 462(b) under the Securities Act, please check the following box and list
the  Securities  Act  registration  statement  number of the  earlier  effective
registration statement for the same offering. |_|______________.

If this Form is a  post-effective  amendment filed pursuant to Rule 462(c) under
the  Securities  Act,  check  the  following  box and  list the  Securities  Act
registration  statement number of the earlier effective  registration  statement
for the same offering. |_|________________.

If delivery  of the  prospectus  is  expected  to be made  pursuant to Rule 434,
please check the following box. |_|



                         CALCULATION OF REGISTRATION FEE



====================================================================================================================================
Title of each class of securities to be       Amount to be        Proposed maximum        Proposed maximum           Amount of
registered                                     registered        offering price per      aggregate offering       registration fee
                                                                      share(1)                  price
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         
Common stock, par value $.15 per share          224,408                $57.30              $12,858,578.40            $1,040.26
====================================================================================================================================


      (1)   Based on the  average of the high and low sale  prices of the common
            stock of Omnicom Group Inc.  reported on the New York Stock Exchange
            on April 4, 2003 of $57.30  per  share,  solely  for the  purpose of
            calculating the registration fee pursuant to Rule 457(c).

The registrant hereby amends this  registration  statement on such date or dates
as may be necessary to delay its effective date until the registrant  shall file
a further amendment which specifically  states that this registration  statement
shall  thereafter  become  effective  in  accordance  with  Section  8(a) of the
Securities  Act of  1933  or  until  the  registration  statement  shall  become
effective on such date as the Commission,  acting pursuant to said Section 8(a),
may determine.


                                       ii



This  information  in this  prospectus  is not complete and may be changed.  The
selling  shareholders  may not sell  these  securities  until  the  registration
statement filed with the Securities and Exchange  Commission is effective.  This
prospectus is not an offer to sell these  securities and it is not soliciting an
offer to buy  these  securities  in any  state  where  the  offer or sale is not
permitted.

                   SUBJECT TO COMPLETION, DATED APRIL 8, 2003

                                   PROSPECTUS

                                  Common Stock

                                 224,408 Shares

                               OMNICOM GROUP INC.

                                   ----------

      This prospectus relates to the public offer for resale by certain of our
shareholders of up to 224,408 shares of our common stock. We issued the shares
in private merger transactions on December 31, 2002. We will not receive any of
the proceeds from the sales of shares by the selling shareholders.

      We have agreed to bear all expenses (other than underwriting discounts and
commissions, fees and expenses of counsel and other advisors to the selling
shareholders, and transfer taxes) in connection with the registration and sale
of the shares covered by this prospectus.

      The selling shareholders may offer and sell from time to time any or all
of the shares of common stock to which this prospectus relates on the New York
Stock Exchange, in privately negotiated transactions or in the over-the-counter
market, or in a combination of those methods, at market prices prevailing at the
time of sale, at prices relating to the prevailing market price, or at
negotiated prices. They may also offer and sell any of the shares in
transactions of the other types described under the heading "Plan of
Distribution." The selling shareholders may be deemed to be underwriters within
the meaning of the Securities Act of 1933, as amended. If any broker-dealers
purchase any shares as principals, any profits received by them on the resale of
such shares may be deemed to be underwriting discounts or commissions under the
Securities Act. In addition, any profits realized by the selling shareholders
may be deemed to be underwriting commissions.

      Our common stock currently trades on the New York Stock Exchange under the
symbol OMC. On April 4, 2003, the last reported sale price for our common stock,
as reported by the New York Stock Exchange, was $57.69 per share.

      We are incorporated in New York. Our principal office is located at 437
Madison Avenue, New York, NY 10022, and our main telephone number is (212)
415-3600.

      Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

                                   ----------

              The date of this Prospectus is ___________ ___, 2003.



                                TABLE OF CONTENTS

FORWARD-LOOKING INFORMATION....................................................3
THE COMPANY....................................................................3
USE OF PROCEEDS................................................................4
DESCRIPTION OF CAPITAL STOCK...................................................4
SELLING SHAREHOLDERS...........................................................5
PLAN OF DISTRIBUTION...........................................................6
EXPERTS........................................................................7
LEGAL MATTERS..................................................................8
WHERE YOU CAN FIND MORE INFORMATION............................................8


                                       2


No person is authorized to give any information or to make any representations,
other than those contained or incorporated by reference in this prospectus in
connection with the offering contemplated hereby, and, if given or made, such
information or representations must not be relied upon as having been authorized
by us or any selling shareholder. This prospectus does not constitute an offer
to sell or a solicitation of an offer to buy any securities other than the
registered securities to which it relates. This prospectus does not constitute
an offer to sell or a solicitation of an offer to buy any securities in any
jurisdiction to any person to whom it is unlawful to make such offer or
solicitation in such jurisdiction. Neither the delivery of this prospectus nor
any sale made hereunder shall, under any circumstances, create any implication
that there has been no change in the affairs of the company since the date of
this prospectus or that the information contained or incorporated by reference
herein is correct as of any time subsequent to its date.

                           FORWARD-LOOKING INFORMATION

      Some of the statements in this prospectus and documents incorporated by
reference constitute "forward-looking statements." These statements relate to
future events or our future financial performance and involve known and unknown
risks, uncertainties and other factors that may cause our or our industry's
actual results, levels of activity, performance or achievements to be materially
different from those expressed or implied by any forward-looking statements.
These uncertainties and risks include, but are not limited to, our future
financial condition and results of operations, changes in general economic
conditions, competitive factors, changes to client communication requirements,
the hiring and retention of human resources and that our international
operations are subject to the risk of currency fluctuations and exchange
controls. In some cases, you can identify forward-looking statements by
terminology such as "may," "will," "could," "would," "should," "expect," "plan,"
"anticipate," "intend," "believe," "estimate," "predict," "potential" or
"continue" or the negative of those terms or other comparable terminology. These
statements are only present expectations. Actual events or results may differ
materially.

                                   THE COMPANY

      We are one of the largest marketing and corporate communications companies
in the world. Marketing and corporate communications services are provided to
clients through global, pan-regional and national independent agency brands. We
provide services to over 5,000 clients in more than 100 countries.

      For additional information regarding our business, see our filings with
the Securities and Exchange Commission, which are incorporated by reference into
this prospectus. Copies of these filings may be obtained as described under
"Where You Can Find More Information." Among other things, the business
description in our Annual Report on Form 10-K for 2002, which we filed with the
SEC on March 26, 2003, contains at page 3 a discussion of business, regulatory
and other risks to which we are subject. In addition, the section of this
prospectus captioned


                                       3


"Experts" on page 7 explains the circumstances involved in our engagement of
KPMG LLP to replace Arthur Andersen LLP as our auditors last year and the
potential effect of Arthur Andersen's ceasing to audit publicly traded companies
on the ability of investors to recover against that firm if the circumstances
would otherwise warrant.

                                 USE OF PROCEEDS

      We will not receive any of the proceeds from sales of the common stock to
which this prospectus relates by the selling shareholders.

                          DESCRIPTION OF CAPITAL STOCK

      The following briefly summarizes the material terms of our capital stock.
You should read our certificate of incorporation, a copy of which may be
obtained from us as described under "Where You Can Find More Information," for
more detailed information that may be important to you.

      We are authorized to issue 1.0 billion shares of common stock, par value
$0.15 per share, of which 188.6 million shares were outstanding on March 17,
2003, and 7.5 million shares of preferred stock, par value $1.00 per share, none
of which is outstanding.

      Each share of common stock entitles the holder to one vote for the
election of directors and for all other matters to be voted on by holders of our
common stock. Holders of common stock may not cumulate their votes in the
election of directors. All shares of common stock have equal rights and are
entitled to such dividends as may be declared by the board of directors out of
funds legally available therefor, but only after payment of dividends required
to be paid on any outstanding shares of preferred stock. All shares of common
stock share ratably upon liquidation in the assets available for distribution to
shareholders after payments to creditors and provision for the preference of any
preferred stock. We are not aware of any restrictions on our present or future
ability to pay dividends. However, in connection with borrowing facilities that
we or our subsidiaries have entered into, we are subject to certain covenants
requiring that we satisfy certain financial tests in order to pay dividends. The
shares of common stock are not subject to call or assessment, have no preemptive
or other subscription rights or conversion rights and cannot be redeemed. We
have a classified board of directors and our shareholders can remove a director
only by an affirmative two-thirds vote of all outstanding voting shares. A
two-thirds vote of all outstanding voting shares is also required to amend our
by-laws or some provisions of our certificate of incorporation and to change the
number of directors comprising the full board. The board of directors has power
to amend the by-laws or change the number of directors comprising the full
board.

      We may issue preferred stock in series having whatever rights and
preferences the board of directors may determine without the approval of our
shareholders. One or more series of preferred stock may be made convertible into
common stock at rates determined by the board of


                                       4


directors, and preferred stock may be given priority over common stock in
payment of dividends, rights on liquidation, voting and other rights.

      Mellon Investor Services, Inc., 44 Wall Street, 6th Floor, New York, New
York 10005, is the transfer agent and the registrar of the common stock. The
common stock is listed on the New York Stock Exchange under the symbol "OMC."

                              SELLING SHAREHOLDERS

      The shares of common stock being offered through this prospectus were
originally issued by us to Alan E. Hall and Alan Hall Family Investments, L.L.C.
in connection with our acquisition of Marketstar Corporation, a Utah
corporation, and Create Marketing and Sales Solutions Inc., a Delaware
corporation, in private transactions exempt from the registration requirements
of the federal securities laws. Alan E. Hall and Alan Hall Family Investments,
L.L.C. transferred the shares of common stock to the selling shareholders in
private transactions exempt from the registration requirements of the federal
securities laws. None of the selling shareholders has had any position, office
or other material relationship with us within the past three years other than as
a result of the ownership of our shares, except that Alan E. Hall, a principal
of Alan Hall Family Investments, L.L.C., The Alan and Jeanne Hall Foundation and
Island Park Group of Companies, was a principal shareholder and executive
officer of Marketstar Corporation and Create Marketing and Sales Solutions Inc.
before we acquired those companies. The information included below is based on
information provided by the selling shareholders.

      Any or all of the common stock listed below may be offered for sale
pursuant to this prospectus by the selling shareholders from time to time.
Accordingly, no estimate can be given as to the amounts of common stock that
will be held by the selling shareholders upon consummation of any such sales. In
addition, the selling shareholders identified below may have sold, transferred,
or otherwise disposed of all or a portion of their shares since the date on
which the information regarding their shares was provided in transactions exempt
from the registration requirements of the Securities Act.

Name                                               Shares Owned   Shares Offered
----                                               ------------   --------------
Alan Hall Family Investments, L.L.C.                   64,024          64,024
The Alan and Jeanne Hall Foundation                    76,279          76,279
Island Park Group of Companies                         61,664          61,664
Corporation of the President of the
  Church of Jesus Christ of
  Latter-day Saints                                    22,441          22,441
                                                      -------         -------
                                                      224,408         224,408
                                                      =======         =======


                                       5


                              PLAN OF DISTRIBUTION

      The shares of common stock covered by this prospectus are being registered
to permit public secondary trading of the shares by the holders thereof from
time to time after the date of this prospectus.

      We have agreed to bear all expenses (other than underwriting discounts and
selling commissions and fees and expenses of counsel and other advisors to
holders of shares) in connection with the registration and sale of the shares
covered by this prospectus. We and the selling shareholders have also agreed to
indemnify each other against certain liabilities arising under the Securities
Act of 1933.

      We have been advised by the selling shareholders that the selling
shareholders may sell all or a portion of the common stock beneficially owned by
them and offered hereby from time to time on any national securities exchange or
quotation service on which the securities are listed, in the over-the-counter
market, in transactions other than on a national exchange or quotation service
or the over-the-counter market, or through the writing of options, in each case
on terms to be determined at the times of such transactions. The selling
shareholders may also make private sales directly or through a broker or
brokers. Alternatively, any of the selling shareholders may from time to time
offer the common stock beneficially owned by them through underwriters, dealers
or agents, who may receive compensation in the form of underwriting discounts,
commissions or concessions from the selling shareholders and the purchasers of
the common stock for whom they may act as agent. The aggregate proceeds to the
selling shareholders from the sale of the common stock offered will be the
purchase price of such common stock less discounts and commissions, if any.

      The common stock may be sold from time to time in one or more transactions
at fixed offering prices, which may be changed, at prevailing market prices at
the time of sale, at varying prices determined at the time of sale, or at
negotiated prices. These prices will be determined by the holders of such
securities or by agreement between these holders and underwriters or dealers who
may receive fees or commissions in connection therewith.

      These transactions may include block transactions or crosses. Crosses are
transactions in which the same broker acts as an agent on both sides of the
trade.

      In connection with sales of the common stock or otherwise, the selling
shareholders may enter into hedging transactions with broker-dealers. These
broker-dealers may in turn engage in short sales of the common stock in the
course of hedging their positions. The selling shareholders may also sell the
common stock short and deliver common stock to close out short positions, or
loan or pledge common stock to broker-dealers that in turn may sell the common
stock.

      Selling shareholders may not sell any or all of the common stock offered
by them pursuant to this prospectus. In addition, we cannot assure you that any
such selling shareholder


                                       6


will not transfer, devise or gift the notes and the underlying common stock by
other means not described in this prospectus. In addition, any shares covered by
this prospectus that qualify for sale pursuant to Rule 144 or Rule 144A of the
Securities Act of 1933 may be sold under Rule 144 or Rule 144A rather than
pursuant to this prospectus.

      The selling shareholders and any broker and any broker-dealers, agents or
underwriters that participate with the selling shareholders in the distribution
of the common stock may be deemed to be "underwriters" within the meaning of the
Securities Act, in which event any commission received by such broker-dealers,
agents or underwriters and any profit on the resale of the notes or the common
stock purchased by them may be deemed to be underwriting commissions or
discounts under the Securities Act.

                                     EXPERTS

      The consolidated financial statements and related 2002 financial statement
schedule of Omnicom Group Inc. as of December 31, 2002, and for the year then
ended, have been incorporated by reference herein in reliance upon the report of
KPMG LLP, independent accountants, incorporated by reference herein, and upon
the authority of said firm as experts in accounting and auditing.

      The consolidated financial statements of Omnicom Group Inc. and
subsidiaries for the years ended December 31, 2000 and 2001 incorporated by
reference in this prospectus and elsewhere in the registration statement have
been audited by Arthur Andersen LLP, independent public accountants, as
indicated in their report with respect thereto, and are included herein in
reliance upon the authority of said firm as experts in giving said report.
Arthur Andersen has not consented to the inclusion or incorporation of their
report in the registration statement and we have dispensed with the requirement
to file their consent in reliance upon Rule 437a of the Securities Act. Because
Arthur Andersen has not consented to the inclusion or incorporation of their
report in the registration statement, it may become more difficult for you to
seek remedies against Arthur Andersen in connection with any material
misstatement or omission that may be contained in our consolidated financial
statements and schedules for such periods. In particular, and without
limitation, you will not be able to recover against Arthur Andersen under
Section 11 of the Securities Act for any untrue statement of a material fact
contained in the financial statements audited by Arthur Andersen or any omission
of a material fact required to be stated in those financial statements.

      In June 2002, our Board of Directors, upon the recommendation of its Audit
Committee, determined not to rehire Arthur Andersen LLP as our independent
accountants and authorized the engagement of KPMG LLP to serve as our
independent accountants for 2002. However, KPMG has not audited the financial
statements that were audited by Arthur Andersen and incorporated herein by
reference.


                                       7


                                  LEGAL MATTERS

      The validity of the shares of common stock offered by this prospectus has
been passed upon for us by Davis & Gilbert LLP, 1740 Broadway, New York, New
York 10019. As of March 10, 2003, members of Davis & Gilbert LLP participating
in the determination of the legality of our shares own an aggregate of 3,860
shares of our common stock.

                       WHERE YOU CAN FIND MORE INFORMATION

      We have filed with the Securities and Exchange Commission a registration
statement on Form S-3 that includes this prospectus. While this prospectus
covers this offering, it does not contain all of the information contained in
the registration statement. You can request a copy of the registration statement
and the exhibits from us to get a more complete description of our company and
this offering. We have provided our address and telephone number below if you
wish to obtain free copies of the registration statement and exhibits.

      We file annual, quarterly and current reports, proxy statements and other
information with the Securities and Exchange Commission. You may read and copy
any document we file at the Commission's public reference room at 450 Fifth
Street, N.W., Washington, D.C. 20549. You can also request copies of these
documents, upon payment of a duplicating fee, by writing the Public Reference
Section of the Commission. Please call the Commission at 1-800-SEC-0330 for
further information on the public reference rooms. Our Commission filings are
also available from the Commission's website at http://www.sec.gov. Reports,
proxy statements and other information filed by us may also be inspected at the
offices of the New York Stock Exchange at 20 Broad Street, New York, New York
10005.

      We are incorporating by reference into this prospectus (and the related
registration statement) certain information we file with the Commission, which
means that we are disclosing important information to you by referring you to
those documents. The information incorporated by reference is considered to be
part of this prospectus except for any information superseded by information
contained directly in this prospectus. Information that we file later with the
Commission will automatically update information in this prospectus. In all
cases you should rely on the later information over different information
included or incorporated by reference into in this prospectus or any prospectus
supplement. We incorporate by reference into this prospectus the following
documents:

      o     Our annual report on Form 10-K for the year ended December 31, 2002;

      o     The description of the common stock contained in the registration
            statement on Form 8-A filed with the SEC pursuant to Section 12 of
            the Exchange Act, including any subsequently filed amendments and
            reports updating such description;


                                       8


      o     All documents and reports we file pursuant to Section 13(a), 13(c),
            14 or 15(d) of the Exchange Act after the date of this prospectus
            and before the filing of a post-effective amendment that indicates
            that all securities that may be offered hereby have been sold or
            that deregisters all securities then remaining unsold.

      Upon written or oral request, we will provide to you, without charge, a
copy of any information incorporated by reference in this prospectus. If you
want more information, write or call us at:

                          Barry J. Wagner, Esq.
                          Secretary and General Counsel
                          Omnicom Group Inc.
                          437 Madison Avenue
                          New York, NY 10022
                          Telephone Number (212) 415-3600

You should rely only on the information provided in this prospectus and the
information incorporated by reference. We have not authorized anyone to provide
you with different information. You should not assume that the information in
this prospectus or any document incorporated by reference is accurate as of any
date other than the date on the front of the applicable document.


                                       9


                                     PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

      Expenses payable in connection with the distribution of the securities
being registered (estimated except for the registration fee), all of which will
be borne by us, are as follows:

            SEC Registration Fee ......................    $ 1,040
            Legal Fees and Expenses ...................    $10,000*
            Accounting Fees ...........................    $ 6,500*
            Miscellaneous Expenses ....................    $ 1,250*
                                                           -------
            TOTAL .....................................    $18,790
                                                           =======

            *  Estimated

Item l5. Indemnification of Directors and Officers.

      Our certificate of incorporation contains a provision limiting the
liability of directors to acts or omissions determined by a judgment or other
final adjudication to have been in bad faith, involving intentional misconduct
or a knowing violation of the law, resulting in personal gain to which the
director was not legally entitled or when such director's acts violated section
719 of the New York Business Corporation Law (approval of statutorily prohibited
dividends, share repurchases or redemptions, distributions of assets on
dissolution or loans to directors). Our by-laws provide that an officer or
director will be indemnified against any costs or liabilities, including
attorney's fees and amounts paid in settlement with our consent 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, that 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 attorneys' 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 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.


                                      II-1


         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 that is settled or otherwise disposed of, or (2) any
claim, issue or matter for which the 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 upon application, that the person is fairly and
reasonably entitled to indemnity for that 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 the section. Section 724 of the
New York Business Corporation Law permits a court to award the indemnification
required by Section 722.

      We have entered into agreements with our 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. We also maintain and
pay premiums for directors' and officers' liability insurance policies.

Item 16. Exhibits.

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

    3.1(a)              Certificate of Incorporation  (incorporated by reference
                        to Omnicom Group Inc.'s  Registration  Statement on Form
                        S-3 (No. 333-46303)).

    3.1(b)              Certificate   of   Amendment  of  the   Certificate   of
                        Incorporation  (incorporated  by  reference  to  Omnicom
                        Group  Inc.'s  Quarterly  Report  on Form  10-Q  for the
                        quarter ended June 30, 2000).

    3.2                 By-laws (incorporated  by  reference  to  Omnicom  Group
                        Inc.'s  Annual  Report on Form  10-K for the year  ended
                        December 31, 1987).


                                      II-2


    5.1                 Opinion of Davis & Gilbert LLP (filed herewith).

    23.1                Consent of KPMG LLP (filed herewith).

    23.2                Consent of Arthur Andersen LLP (omitted).*

    23.3                Consent of Davis & Gilbert LLP  (included in the opinion
                        filed as Exhibit No. 5.1).

----------
*     The consent of Arthur Andersen LLP, the former independent accountants for
      the Registrant as of December 31, 2000 and 2001 and for the years then
      ended, could not be obtained after reasonable efforts and, accordingly, is
      being omitted pursuant to Rule 437a under the Securities Act of 1933.

Item 17. Undertakings.

         We undertake:

      (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 this registration statement (or the most
            recent post-effective amendment thereof) that, individually or in
            the aggregate, represent a fundamental change in the information in
            this registration statement. Notwithstanding the foregoing, any
            increase or decrease in volume of securities offered (if the total
            dollar value of securities offered would not exceed that which was
            registered) and any deviation from the low or high end of the
            estimated maximum offering range may be reflected in the form of
            prospectus filed with the Securities and Exchange Commission
            pursuant to Rule 424(b) if, in the aggregate, the changes in volume
            and price represent no more than a 20 percent change in the maximum
            aggregate offering price set forth in the "Calculation of
            Registration Fee" table in the effective registration statement; and

            (iii) To include any material information with respect to the plan
            of distribution not previously disclosed in this registration
            statement or any material change to such information in the
            registration statement;


                                      II-3


      Provided, however, paragraphs (1)(i) and (1)(ii) shall not apply if the
information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by us pursuant to Section 13
or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by
reference in this 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 the securities at that time shall be deemed to be the initial bona
fide offering thereof.

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

      We further undertake that, for purposes of determining any liability under
the Securities Act of 1933, each filing of our annual report pursuant to Section
13(a) or 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 therein, and the offering of the
securities at that time shall be deemed to be the initial bona fide offering
thereof.

      Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers or persons controlling the
registrant, pursuant to the provisions described under Item 15 above or
otherwise, the registrant has been advised that in the opinion of the Securities
and Exchange Commission the 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-4


                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this registration
statement on Form S-3 to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of New York, in the State of New York on April 8,
2003.

                                       OMNICOM GROUP INC.,
                                         as Registrant

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

                                   ----------

      KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints John D. Wren and Barry J. Wagner, Esq., and each
of them, his true and lawful attorney-in-fact and agent, with full and several
power of substitution and resubstitution, for him and in his name, place and
stead, in any and all capacities, to sign any or all amendments, to this
registration statement, and to file the same, with all exhibits thereto, and
other documents in connection therewith, with the Securities and Exchange
Commission, granting unto said attorneys-in-fact and agent full power and
authority to do and perform each and every act and thing requisite and necessary
to be done in and about the premises, as fully to all intents and purposes as
they or he might or could do in person, hereby ratifying and confirming all that
said attorneys-in-fact and agents or his substitute or substitutes, may lawfully
do or cause to be done by virtue hereof.

      Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement on Form S-3 has been signed below by the following
persons in the capacities and on the dates indicated.

/s/ John D. Wren                 President, Chief Executive        April 8, 2003
-----------------------------       Officer and Director
    John D. Wren                (Principal Executive Officer)

/s/ Randall J. Weisenburger      Executive Vice President          April 8, 2003
-----------------------------   and Chief Financial Officer
    Randall J. Weisenburger     (Principal Financial Officer)


                                      II-5


/s/ Philip J. Angelastro          Senior Vice President of         April 8, 2003
-----------------------------      Controller Finance and
    Philip J. Angelastro       (Principal Accounting Officer)

/s/ Bruce Crawford                        Director                 April 8, 2003
-----------------------------
    Bruce Crawford

/s/ Robert Charles Clark                  Director                 April 8, 2003
-----------------------------
    Robert Charles Clark

/s/ Leonard S. Coleman, Jr.               Director                 April 8, 2003
-----------------------------
    Leonard S. Coleman, Jr.

/s/ Errol M. Cook                         Director                 April 8, 2003
-----------------------------
    Errol M. Cook

/s/ Susan S. Denison                      Director                 April 8, 2003
-----------------------------
    Susan S. Denison

                                          Director                 April _, 2003
-----------------------------
     Michael A. Henning

/s/ John R. Murphy                        Director                 April 8, 2003
-----------------------------
    John R. Murphy

/s/ John R. Purcell                       Director                 April 8, 2003
-----------------------------
    John R. Purcell


                                      II-6


                                          Director                 April _, 2003
-----------------------------
    Linda Johnson Rice

/s/ Gary L. Roubos                        Director                 April 8, 2003
-----------------------------
    Gary L. Roubos


                                      II-7