As filed with the Securities and Exchange Commission on April 13, 2000
                                                    Registration No. 333-
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-4
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                    THE INTERPUBLIC GROUP OF COMPANIES, INC.
             (Exact name of Registrant as specified in its charter)

         Delaware                       7311                    13-1024020
(State or other jurisdiction      (Primary Standard          (I.R.S. Employer
     of incorporation         Industrial Classification   Identification Number)
     or organization)                Code Number)

                           1271 Avenue of the Americas
                            New York, New York 10020
                                 (212) 399-8000

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

                   Nicholas J. Camera, Senior Vice President,
                           General Counsel & Secretary
                    The Interpublic Group of Companies, Inc.
                           1271 Avenue of the Americas
                            New York, New York 10020
                                 (212) 399-8000

       (Name, address, including zip code, and telephone number, including
                   area code, of agent for service) Copies to:

         Barry M. Fox, Esq.                       James M. Dubin, Esq.
 Cleary, Gottlieb, Steen & Hamilton     Paul, Weiss, Rifkind, Wharton & Garrison
          One Liberty Plaza                    1285 Avenue of the Americas
      New York, New York 10006                  New York, New York 10019
           (212) 225-2000                            (212) 373-3000


                  Approximate date of commencement of proposed sale to the
public: As soon as practicable after the effective date of this Registration
Statement which relates to the issuance of common stock of The Interpublic Group
of Companies, Inc. in the merger of NFO Worldwide, Inc. with a wholly owned
subsidiary of The Interpublic Group of Companies, Inc. pursuant to the Agreement
and Plan of Merger, dated December 20, 1999, as amended.

                  If the securities being registered on this Form are being
offered in connection with the formation of a holding company and there is
compliance with General Instruction G, please check the following box. |_|

                  If this Form is filed to register additional securities for an
offering pursuant to Rule 462(b) 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: [X] 333-31436

                  If this Form is a post-effective amendment filed pursuant to
Rule 462(d) 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: |_|


                                       CALCULATION OF REGISTRATION FEE
- ---------------------------------------------------------------------------------------------------------------
          Securities to be             Amount to    Proposed Maximum    Proposed Maximum
             Registered                   be         Offering Price        Aggregate            Amount of
       Title of Each Class of        Registered(1)     Per Share       Offering Price (2)  Registration Fee (2)
- ---------------------------------------------------------------------------------------------------------------
                                                                               
Common Stock, $.01 par value ......     692,258           N/A            $30,898,765.31          $8157.27
- ---------------------------------------------------------------------------------------------------------------
(1)  The Registrant, The Interpublic Group of Companies, Inc. ("IPG"),
     previously filed a registration statement on Form S-4 (Commission File No.
     333-31436) to cover 14,042,025 shares (the "Initial Shares") of IPG's
     common stock, $.01 par value ("IPG Common Stock"), issuable in connection
     with the merger of a wholly owned subsidiary of IPG with and into NFO
     Worldwide, Inc. ("NFO"). IPG is filing this registration statement on Form
     S-4 pursuant to Rule 462(b) with respect to an additional 692,258 shares of
     IPG Common Stock issuable in connection with the merger based on an
     increase in the maximum exchange ratio contemplated by the merger agreement
     from 0.5274 to 0.5503.
(2)  At the maximum exchange ratio of 0.5503, 1,257,965 shares of NFO common
     stock would be cancelled in the transaction in exchange for the additional
     692,258 shares of IPG Common Stock registered hereby. The Proposed Maximum
     Aggregate Offering Price and the Amount of Registration Fee are based on
     this number of shares of NFO Common Stock and, pursuant to Rules 457(f) and
     457(c) under the Securities Act of 1933, as amended, the average of the
     high and low sale prices of NFO common stock, as reported by the New York
     Stock Exchange, Inc. on April 12, 2000. IPG previously paid a registration
     fee of $127,400.63 in connection with the registration of the Initial
     Shares. In accordance with Rule 457(a), the shares of NFO common stock that
     would be cancelled in the transaction in exchange for the Initial Shares
     have been excluded from the calculation of the amount of the registration
     fee payable in connection with this registration statement.

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



         Explanatory Note and Incorporation of Information by Reference

         This Registration Statement is being filed pursuant to Rule 462(b)
under the Securities Act of 1933, as amended, and relates to the offering of
shares of Common Stock of The Interpublic Group of Companies, Inc. ("IPG") in
connection with its acquisition of NFO Worldwide, Inc. as described in the
registration statement on Form S-4, Registration No. 333-31436, as amended (the
"Prior Registration Statement"). This Registration Statement is being filed to
register an additional 692,258 shares of Common Stock of IPG for issuance in
connection with that acquisition. The contents of the Prior Registration
Statement, including all exhibits thereto, are hereby incorporated by reference.


                                    Exhibits

     5.1    Opinion of Nicholas J. Camera, Esq. as to the legality of the
            issuance of the shares of common stock offered hereby

     8.1    Opinion of Paul, Weiss, Rifkind, Wharton & Garrison as to U.S. tax
            matters

     8.2    Opinion of Cleary, Gottlieb, Steen & Hamilton as to U.S. tax matters

     23.1   Consent of PricewaterhouseCoopers LLP (relating to financial
            statements of The Interpublic Group of Companies, Inc.)

     23.2   Consent of Arthur Andersen LLP (relating to financial statements of
            NFO Worldwide, Inc.)

     23.3   Consent of Soteriou Banerji (relating to financial statements of The
            MBL Group plc included in the financial statements of NFO Worldwide,
            Inc.)

     23.4   Consent of Haarmann, Hemmelrath & Partner GmbH (relating to
            financial statements of Infratest Burke Aktiengesellschaft Holding,
            a subsidiary of NFO Worldwide, Inc.)

     23.5   Consent of Ernst & Young LLP (relating to financial statements of
            Hill, Holliday, Connors, Cosmopulos, Inc. included in the financial
            statements of The Interpublic Group of Companies, Inc.)

     23.6   Consent of Ernst & Young (relating to financial statements of
            International Public Relations plc included in the financial
            statements of The Interpublic Group of Companies, Inc.)

     24.1   Powers of Attorney (Incorporated by reference to The Interpublic
            Group of Companies, Inc.'s Registration Statement on Form S-4, File
            No. 333-31436)

     99.5   Consent of Greenhill & Co., LLC


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant 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 April 13, 2000.

                                     THE INTERPUBLIC GROUP OF COMPANIES, INC.


                                     By: /s/ Nicholas J. Camera
                                         -----------------------------
                                         Name:   Nicholas J. Camera
                                         Title:  Vice President



         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.



            Signature                                  Title                           Date
            ---------                                  -----                           ----
                                                                             
               *
- --------------------------------    Chairman of the Board, President and Chief     April 13, 2000
      Philip H. Geier, Jr.            Executive Officer (Principal Executive
                                               Officer) and Director

               *
- --------------------------------     Executive Vice President, Chief Financial     April 13, 2000
          Sean F. Orr                Officer (Principal Financial Officer) and
                                                     Director

               *
- --------------------------------           Vice President and Controller           April 13, 2000
         Frederick Molz                   (Principal Accounting Officer)

               *
- --------------------------------                     Director                      April 13, 2000
        Frank J. Borelli

               *
- --------------------------------                     Director                      April 13, 2000
       Reginald K. Brack

               *
- --------------------------------                     Director                      April 13, 2000
        Jim M. Considine

               *
- --------------------------------                     Director                      April 13, 2000
      John J. Dooner, Jr.

               *
- --------------------------------                     Director                      April 13, 2000
         Frank B. Lowe

               *
- --------------------------------                     Director                      April 13, 2000
        Michael A. Miles

               *
- --------------------------------                     Director                      April 13, 2000
         Lief H. Olsen

               *
- --------------------------------                     Director                      April 13, 2000
         Allen Questrom

               *
- --------------------------------                     Director                      April 13, 2000
       J. Phillip Samper


*    By:  /s/ Nicholas J. Camera
          -----------------------------
     Name:  Nicholas J. Camera
     Title:  Attorney-in-Fact


                                  EXHIBIT INDEX

    EXHIBIT NUMBER                                               DESCRIPTION

          5.1       Opinion of Nicholas J. Camera, Esq. as to the legality of
                    the issuance of the shares of common stock offered hereby

          8.1       Opinion of Paul, Weiss, Rifkind, Wharton & Garrison as to
                    U.S. tax matters

          8.2       Opinion of Cleary, Gottlieb, Steen & Hamilton as to U.S. tax
                    matters

          23.1      Consent of PricewaterhouseCoopers LLP (relating to financial
                    statements of The Interpublic Group of Companies, Inc.)

          23.2      Consent of Arthur Andersen LLP (relating to financial
                    statements of NFO Worldwide, Inc.)

          23.3      Consent of Soteriou Banerji (relating to financial
                    statements of The MBL Group plc included in the financial
                    statements of NFO Worldwide, Inc.)

          23.4      Consent of Haarmann, Hemmelrath & Partner GmbH (relating to
                    financial statements of Infratest Burke Aktiengesellschaft
                    Holding, a subsidiary of NFO Worldwide, Inc.)

          23.5      Consent of Ernst & Young LLP (relating to financial
                    statements of Hill, Holliday, Connors, Cosmopulos, Inc.
                    included in the financial statements of The Interpublic
                    Group of Companies, Inc.)

          23.6      Consent of Ernst & Young (relating to financial statements
                    of International Public Relations plc included in the
                    financial statements of The Interpublic Group of Companies,
                    Inc.)

          24.1      Powers of Attorney (Incorporated by reference to The
                    Interpublic Group of Companies, Inc.'s Registration
                    Statement on Form S-4, File No. 333-31436)

          99.5      Consent of Greenhill & Co., LLC

                                                                     Exhibit 5.1

                                     April 11, 2000


The Interpublic Group of Companies, Inc.,
1271 Avenue of the Americas
New York, New York 10020

         Re:   The Interpublic Group of Companies, Inc.
               Registration Statement on Form S-4

Ladies and Gentlemen:

         I am General Counsel of The Interpublic Group of Companies, Inc., a
Delaware corporation (the "Corporation"), in connection with the preparation and
filing with the Securities and Exchange Commission (the "Commission") under Rule
462(b) of the Securities Act of 1933, as amended (the "Act"), of the
above-captioned Registration Statement on Form S-4 (the "Registration
Statement"), relating to the registration of 692,258 shares of the Corporation's
Common Stock, $.10 par value (the "Shares").

         In arriving at the opinions expressed below, I have examined and relied
on the originals or copies certified or otherwise identified to my satisfaction
of all such corporate records of the Corporation and such other instruments and
other certificates or public officials, officers and representatives of the
Corporation and such other persons, and I have made such investigation of law,
as I have deemed appropriate as a basis for the opinions expressed below. In
rendering the opinions expressed below, I have assumed and have not verified
that the signatures on all documents that I have examined are genuine.

         Based on the foregoing, it is my opinion that:

         1. The Corporation is validly existing as a corporation in good
standing under the laws of the State of Delaware.

         2. The Shares have been duly authorized by all necessary corporate
action of the Corporation, and are legally issued, fully paid and
non-assessable.

         Insofar as the foregoing opinions relate to the validity, binding
effect or enforceability of any agreement or obligations of the Company, (a) I
have assumed that each other party to such agreement or obligation has satisfied
those legal requirements that are applicable and it to the extent necessary to
make such agreement or obligation enforceable against it, and (b) such opinions
are subject to applicable bankruptcy, insolvency and similar laws affecting
creditors' rights generally and to general principals of equity.

         I hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to my name in the Registration
Statement. By giving such consent, I do not admit that I am an "expert" within
the meaning of the Act or the rules and regulations of the Commission issued
thereunder with respect to any part of the Registration Statement, including
this exhibit.

                                       Very truly yours,


                                       /s/ Nicholas J. Camera
                                       ----------------------------
                                       Nicholas J. Camera

                                                                     Exhibit 8.1



                                       April 12, 2000


NFO Worldwide, Inc.
2 Pickwick Plaza, Suite 400
Greenwich, CT 06830-5530

Ladies and Gentlemen:

         You have requested our opinion as to whether the proposed merger of
Merger Sub, a to-be-formed Delaware corporation wholly owned by The Interpublic
Group of Companies, Inc., a Delaware corporation ("Parent"), with and into NFO
Worldwide, a Delaware corporation (the "Company"), with the Company being the
surviving corporation (the "Merger") should be treated for United States federal
income tax purposes as a reorganization under the provisions of Section 368(a)
of the Internal Revenue Code of 1986, as amended (the "Code").

         In reaching the opinions expressed below, we have reviewed and relied
on (i) the Agreement and Plan of Merger ("the Merger Agreement"), dated as of
December 20, 1999, as amended on April 3, 2000, by and among Parent and the
Company, (ii) the representation letters addressed to us in connection with the
opinion set forth below from Parent and the Company, (iii) the Registration
Statement on Form S-4 (the "Registration Statement") to be filed by Parent with
the Securities and Exchange Commission on April 12, 2000, and (v) such other
information and materials as we have deemed appropriate.

         We have assumed, without any independent investigation, that the Merger
Agreement has been duly authorized, executed and delivered by the parties to it
and constitutes the valid and legally binding obligation of the parties, that
the Merger Agreement has not been and will not be further amended or modified,
that the representations and warranties in the Merger Agreement are and will
continue to be accurate, that parties to the Merger Agreement will act in
accordance with it, and that there are and will be no other agreements or
understandings among the parties in connection with the subject matter of the
Merger Agreement.

         We have examined those corporate records, certificates and other
documents as we have considered necessary or appropriate for the purposes of
this opinion. In this examination, we have assumed the genuineness of all
signatures, the authenticity of all documents submitted to us as originals, the
conformity to the originals of all documents submitted to us as copies, and the
legal capacity of all individuals who have executed any of the documents
reviewed by us. In rendering our opinion set forth below, we have relied as to
factual matters upon information obtained from Parent and the Company, their
officers and representatives and public officials.

         Based upon and subject to the foregoing, it is our opinion that the
Merger will qualify for United States federal income tax purposes as a
reorganization under the provisions of Section 368(a) of the Code.

         We express no opinion concerning any United States, state, local or
foreign tax matter relating to the Merger or other matter, except as expressly
set forth above.

         The above opinion is based on the current provisions of the Code and
the regulations under it, and on current interpretations of the Code and the
regulations. The Code, the regulations and the interpretations described above
are subject to change at any time, possibly with retroactive effect. Any change
could affect the continuing validity of the opinion set forth above. We assume
no responsibility to advise you of any subsequent changes in existing law or
facts, nor do we assume any responsibility to update this opinion with respect
to any matters expressly set forth and no opinions are to be implied or may be
inferred beyond the matters expressly so stated. No ruling has been (or will be)
sought from the Internal Revenue Service (the "IRS") as to the federal income
tax consequences of any aspect of the Merger, and there can be no assurance that
the IRS or any court of competent jurisdiction will not disagree with the
opinions expressed herein.

         This letter is furnished by us solely for your benefit and the benefit
of holders of outstanding Company stock and may not be relied on in any manner
or for any purpose by any other person or entity without our prior written
consent.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.

                                    Very truly yours,


                          PAUL, WEISS, RIFKIND, WHARTON & GARRISON

                                                                     Exhibit 8.2





Writer's Direct Dial:  (212) 225-2480

                                                    April 12, 2000


The Interpublic Group of Companies, Inc.
1271 Avenue of the Americas
New York, NY 10020

Ladies and Gentlemen:

         We have acted as counsel to The Interpublic Group of Companies, Inc., a
Delaware corporation ("Parent") in connection with the transactions contemplated
by the Agreement and Plan of Merger dated as of December 20, 1999 and amended as
of April 3, 2000 (the "Agreement") by and between NFO Worldwide, Inc., a
Delaware corporation (the "Company") and Parent (such transactions, the
"Merger"). At your request, in connection with the filing of a registration
statement on Form S-4 (the "S-4") on the date hereof with the SEC in connection
with the Merger, we are rendering our opinion with regard to certain United
States federal income tax consequences of the Merger. All capitalized items used
but not defined herein shall have the same meanings as in the Agreement.

         In arriving at the opinion expressed below, we have examined and relied
upon the accuracy and completeness of the facts, information, covenants and
representations contained in originals, or copies certified or otherwise
identified to our satisfaction, of: the Agreement, the S-4, certificates and
representations of officers and representatives of Parent and the Company and
such other persons as we have deemed necessary or appropriate, and such other
documents as we have deemed necessary or appropriate as a basis for the opinion
set forth below.

         Without limiting the generality of the foregoing, in arriving at the
opinion expressed below, we have also examined and relied, without independent
verification of the statements contained therein, on letters from each of Parent
and the Company regarding certain tax matters, and we have assumed the accuracy
of the representations and statements made in each of the foregoing.

         In arriving at the opinion expressed below, we have assumed, without
making any independent investigation, that all such documents as furnished to us
are complete and authentic, that the signatures on all documents are genuine,
and that all such documents have been, or in the case of drafts, will be, duly
authorized, executed and delivered. We have further assumed that the
transactions will be consummated and the parties will act in accordance with
these documents.

         The opinion expressed below is based on the Internal Revenue Code of
1986, as amended, (the "Code"), and applicable regulations, rulings and
decisions, in each case as in effect on the date hereof, and may be affected by
amendments to the Code or to the regulations thereunder or by subsequent
judicial or administrative interpretations thereof. We express no opinion herein
other than as to the federal income tax laws of the United States.

         Based on and subject to the foregoing, it is our opinion that the
Merger will constitute a reorganization within the meaning of section 368(a) of
the Code.

         We hereby consent to the use of our name and the making of statements
with respect to us in the Proxy Statement under the heading "THE MERGER - U.S.
Federal Income Tax Consequences of the Merger." In giving this consent, we do
not hereby admit that we are in the category of persons whose consent is
required under Section 7 of the Securities Act of 1933, as amended, or the rules
and regulations of the Securities and Exchange Commission thereunder.

                                    Very truly yours,

                                    CLEARY, GOTTLIEB, STEEN & HAMILTON

                                    By:  /s/ Edward D. Kleinbard
                                         ----------------------------------
                                         Edward D. Kleinbard, a Partner
                                                                    Exhibit 23.1

                       CONSENT OF INDEPENDENT ACCOUNTANTS
                       ----------------------------------


We hereby consent to the incorporation by reference in this Registration
Statement on Form S-4 of The Interpublic Group of Companies (the "Company") of
our report dated February 22, 2000 relating to the financial statements, which
appears in the 1999 Annual Report to the Stockholders of the Company, which is
incorporated by reference in the Company's Annual Report on Form 10-K for the
year ended December 31, 1999. We also consent to the incorporation by reference
of our report dated February 22, 2000 relating to the Financial Statement
Schedule, which appears in such Annual Report on Form 10-K. We also consent to
the reference to us under the heading "Experts" in such Registration Statement.


                                           PRICEWATERHOUSECOOPERS LLP


New York, New York
April 12, 2000

                                                                   Exhibit 23.2

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS



As independent public accountants, we hereby consent to the use of our report
dated February 25, 2000, on the consolidated financial statements of NFO
Worldwide, Inc. and subsidiaries as of December 31, 1999 and 1998, and for each
of the years in the three year period ended December 31, 1999, included in or
made a part of this registration statement and to all references to our firm
included in this registration statement.




                                           ARTHUR ANDERSEN LLP



New York, New York,
  April 10, 2000.

                                                                    Exhibit 23.3

            CONSENT OF REGISTERED AUDITORS AND CHARTERED ACCOUNTANTS

As registered auditors and chartered accountants, we hereby consent to the use
of our report dated February 23, 1998, on the financial statements of The MBL
Group Plc for the year ended December 31, 1997, included in or made a part of
this registration statement and to all references to our firm included in this
registration statement.




                                                                SOTERIOU BANERJI


London, England,
      April 12, 2000


                                                                    Exhibit 23.4

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the use of our report
dated January 15, 1999, on the consolidated financial statements of Infratest
Burke Aktiengesellschaft Holding and subsidiaries as of September 30, 1998, 1997
and 1996, and for each of the years in the three year period ended September 30,
1998, included in or made a part of this registration statement and to all
references to our firm included in this registration statement.



Munich / Germany, April 12, 2000

                                          Haarmann, Hemmelrath & Partner GmbH
                                            Wirtschaftsprufungsgesellschaft
                                              Steuerberatungsgesellschaft



                                                                   Exhibit 23.5



                         CONSENT OF INDEPENDENT AUDITORS



     We consent to the incorporation in the Registration Statement (Form S-4) of
The Interpublic Group of Companies, Inc. for the registration of shares of its
common stock of our report dated March 13, 1998, with respect to the
consolidated financial statements of Hill, Holliday, Connors, Cosmopulos, Inc.
for the twelve month period ended December 31, 1997, which statements are
included in the consolidated financial statements of IPG for the year ended
December 31, 1997 incorporated by reference in its Annual Report on Form 10-K
for the year ended December 31, 1999, filed with the Securities and Exchange
Commission.

                                                              ERNST & YOUNG LLP



April 12, 2000
Boston, Massachusetts
                                                                    Exhibit 23.6







                         CONSENT OF INDEPENDENT AUDITORS

We consent to the reference to our firm in the Registration Statement (Form S-4)
and related Prospectus of NFO Worldwide, Inc. for the registration of shares of
common stock of The Interpublic Group of Companies, Inc. and to the
incorporation by reference therein of our report dated February 3, 1999, with
respect to the consolidated financial statements of International Public
Relations plc which is included in the Annual Report (Form 10-K) of The
Interpublic Group of Companies, Inc. for the year ended December 31, 1999, filed
with the Securities and Exchange Commission.


                                                                   Ernst & Young
April 12, 2000
London, England

                                                                    Exhibit 99.5


                                   CONSENT OF
                              GREENHILL & CO., LLC


                                                       April 12, 2000


NFO Worldwide, Inc.
2 Pickwick Plaza
Greenwich, CT  06830

Dear Sirs:

     We refer to the Registration Statement (the "Registration Statement") of
The Interpublic Group of Companies, Inc. ("Interpublic") on Form S-4, with
respect to the shares of common stock, par value $.10 per share, of Interpublic
to be issued to stockholders of NFO Worldwide, Inc. ("NFO") in connection with
the merger of a subsidiary of Interpublic with NFO.

     We hereby consent to the inclusion of our opinion letter dated December 19,
1999 to the Board of Directors of NFO appearing as Annex C to the Registration
Statement, and to the references of our firm name therein. In giving such
consent, we do not thereby admit that we come within the category of persons
whose consent is required under Section 7 of the Securities Act of 1933, as
amended, or the rules and regulations adopted by the Securities and Exchange
Commission thereunder, nor do we thereby admit that we are experts with respect
to any part of such Registration Statement within the meaning of the term
"experts" as used in the Securities Act of 1933, as amended, or the rules and
regulations of the Securities and Exchange Commission thereunder.

                                      Very truly yours,

                                      GREENHILL & CO. LLC



                                      By:     /s/  Robert F. Greenhill
                                              ------------------------
                                      Name:   Robert F. Greenhill
                                      Title:  Chairman