EXHIBIT 99.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER I, R. Douglas Armstrong, Chief Executive Officer of Aastrom Biosciences, Inc. (the "Registrant"), do hereby certify in accordance with 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that: (1) the Quarterly Report on Form 10-Q of the Registrant, to which this certification is attached as an exhibit (the "Report"), fully complies with the requirements of section 13(a) of the Securities Exchange Act of 1934 (15 U.S.C. 78m); and (2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant. Dated: November 13, 2002 /s/ R. Douglas Armstrong ------------------------------------- R. Douglas Armstrong, Ph.D. President and Chief Executive Officer