EXHIBIT 99.1 CERTIFICATION OF PERIODIC REPORT Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, Roy W. Spradlin, Chairman, President, and CEO of U.S. Physical Therapy, Inc. (the "Company") and J. Michael Mullin, Chief Financial Officer of the Company, certify that: (1) the Quarterly Report on Form 10-Q of the Company for the period ended March 31, 2003, as filed with the Securities and Exchange Commission on the date hereof (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/ Roy Spradlin ------------------------------------ Name: Roy W. Spradlin Title: Chairman, President and CEO Date: May 15, 2003 /s/ J. Michael Mullin ------------------------------------ Name: J. Michael Mullin Title: Chief Financial Officer Date: May 15, 2003 This certification is made solely pursuant to the requirement of Section 1350 of 18 U.S.C., and is not for any other purpose. 20