EXHIBIT (99.1) CEO CERTIFICATION OF PERIODIC REPORT

                        CERTIFICATION OF PERIODIC REPORT

I, Ralph W. Babb, Jr. of Comerica Incorporated (the "Company"), certify,
pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section
1350, that:

(1)   The Quarterly Report on Form 10-Q of the Company for the quarterly period
      ended September 30, 2002 (the "Report") fully complies with the
      requirements of Section 13(a) or 15(d) of the Securities Exchange Act of
      1934 (15 U.S.C. 78m or 78o(d)); and

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

Dated: November 12, 2002

                                             /s/ Ralph W. Babb, Jr.
                                             ---------------------------
                                             Ralph W. Babb, Jr.
                                             Chairman, President and
                                             Chief Executive Officer