Exhibit 99.1 ------------ ADDITIONAL CERTIFICATIONS Pursuant to 18 U.S.C. ss. 1350, the undersigned officer of Michael Baker Corporation (the "Company"), hereby certifies that the Company's Quarterly Report on Form 10-Q for the quarter ended March 31, 2003 (the "Report") fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934 and that the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. /s/ Donald P. Fusilli, Jr. Dated: May 30, 2003 - ---------------------------------------- Donald P. Fusilli, Jr. President and Chief Executive Officer Pursuant to 18 U.S.C. ss. 1350, the undersigned officer of Michael Baker Corporation (the "Company"), hereby certifies that the Company's Quarterly Report on Form 10-Q for the quarter ended March 31, 2003 (the "Report") fully complies with the requirements of Section 13(a) or 15(d), as applicable, of the Securities Exchange Act of 1934 and that the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company. /s/ Willam P. Mooney Dated: May 30, 2003 - ---------------------------------------- William P. Mooney Executive Vice President and Chief Financial Officer These additional certifications are being furnished solely pursuant to 18 U.S.C. Section 1350, and are not being filed as part of the Report or as a separate disclosure document. -23-