EXHIBIT 99.1

    CERTIFICATION 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 annual report of United Auto Group, Inc. (the
"Company") on Form 10-K for the period ending December 31, 2002 as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Roger S. Penske, Chief Executive Officer of the Company, certify, pursuant to 18
U.S.C. ss. 1350, as adopted pursuant to ss. 906 of the Sarbanes-Oxley Act of
2002, that:

     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.


/s/ Roger S. Penske
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Roger S. Penske
Chairman of the Board,
Chief Executive Officer

March 26, 2003