Exhibit 99.1 Chief Executive Officer and Chief Financial Officer Certification pursuant to 18 U.S.C. Section 1350 PART II. OTHER INFORMATION FORM 10-Q CERTIFICATION OF FINANCIAL RESULTS We, Norman L. Lowery, Vice Chairman and CEO, and Michael A. Carty, Chief Financial Officer, of First Financial Corp., hereby individually certify the following: - - This Form 10-Q fully complies with the requirements of Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, and, - - The information contained in the report fairly presents, in all material respects, the financial position and results of operations of First Financial Corp. as of and for the periods presented. May 9, 2003 By /s/ NORMAN L. LOWERY ----------------------------------------- Norman L. Lowery Vice Chairman, & CEO May 9, 2003 By /s/ MICHAEL A. CARTY ----------------------------------------- Michael A. Carty, Treasurer & CFO