EXHIBIT 99.1

                    CERTIFICATION OF CEO AND CFO PURSUANT TO
                            18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                 SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

     In connection with the Quarterly Report on Form 10-Q of Grey Global Group
Inc. (the "Company") for the quarterly period ending March 31, 2003 as filed
with the Securities and Exchange Commission on the date hereof (the "Report"),
Edward H. Meyer, as Chief Executive Officer of the Company, and Steven G.
Felsher, as Chief Financial Officer of the Company, each hereby certifies,
pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002, that, to the best of his knowledge(1):

          (1) The Report fully complies with the requirements of Section 13(a)
     or 15(d) of the Securities Exchange Act of 1934; and

          (2) The information contained in the Report fairly presents, in all
     material respects, the financial condition and results of operations of the
     Company.

                                          By: /s/ EDWARD H. MEYER
                                            ------------------------------------
                                          Name: Edward H. Meyer
                                          Title: Chief Executive Officer
                                          Date: May 15, 2003

                                          By: /s/ STEVEN G. FELSHER
                                            ------------------------------------
                                          Name: Steven G. Felsher
                                          Title: Chief Financial Officer
                                          Date: May 15, 2003

This certification accompanies the Report pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the
Sarbanes-Oxley Act of 2002, be deemed filed by the Company for purposes of
Section 18 of the Securities Exchange Act of 1934, as amended.