EXHIBIT 99.1
CERTIFICATION OF CHIEF EXECUTIVE OFFICER






                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Pharmaceutical  Resources,  Inc. (the
"Company")  on Form 10-Q for the period  ended  March 30, 2003 as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, Kenneth
I.  Sawyer,  Chief  Executive  Officer of the Company,  certify,  pursuant to 18
U.S.C.  Section 1350, as adopted  pursuant to Section 906 of the  Sarbanes-Oxley
Act of 2002, that, to my knowledge:

    (1) 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  result of  operations  of the
        Company.


/s/ KENNETH I. SAWYER
- ---------------------
Kenneth I. Sawyer
Chief Executive Officer
May 14, 2003