EXHIBIT 31.1


          CERTIFICATION PURSUANT TO RULE 13A-14(A) OF THE EXCHANGE ACT


      I,  Scott  L.   Tarriff,   President  and  Chief   Executive   Officer  of
      Pharmaceutical Resources, Inc., certify that:

1.    I have  reviewed  this  quarterly  report on Form  10-Q of  Pharmaceutical
      Resources, Inc.;

2.    Based on my knowledge,  this quarterly  report does not contain any untrue
      statement of a material fact or omit to state a material fact necessary to
      make the statements made, in light of the  circumstances  under which such
      statements were made, not misleading with respect to the period covered by
      this quarterly report;

3.    Based on my  knowledge,  the  financial  statements,  and other  financial
      information  included  in this  quarterly  report,  fairly  present in all
      material respects the financial condition,  results of operations and cash
      flows of the  registrant  as of, and for,  the periods  presented  in this
      quarterly report;

4.    The  registrant's  other  certifying  officer  and I are  responsible  for
      establishing  and  maintaining  disclosure  controls  and  procedures  (as
      defined in Exchange Act Rules  13a-15(e) and 15d-15(e)) for the registrant
      and we have:

      a)   designed  such  disclosure  controls and  procedures,  or caused such
           disclosure   controls  and   procedures  to  be  designed  under  our
           supervision,  to ensure  that  material  information  relating to the
           registrant, including its consolidated subsidiaries, is made known to
           us by others within those entities, particularly during the period in
           which this quarterly report is being prepared;

      b)   evaluated the effectiveness of the registrant's  disclosure  controls
           and procedures and presented in this report our conclusions about the
           effectiveness  of the disclosure  controls and procedures,  as of the
           end of the period covered by this report,  based on such  evaluation;
           and

      c)   disclosed  in this  report  any change in the  registrant's  internal
           control  over   financial   reporting   that   occurred   during  the
           registrant's most recent fiscal quarter that has materially affected,
           or  is  reasonably  likely  to  materially  affect  the  registrant's
           internal control over financial reporting;

5.    The registrant's other certifying  officer and I have disclosed,  based on
      our most recent  evaluation of internal control over financial  reporting,
      to the  registrant's  auditors and the audit committee of the registrant's
      board of directors:

      a)   all significant deficiencies and material weaknesses in the design or
           operation of internal  controls over  financial  reporting  which are
           reasonably  likely to adversely  affect the  registrant's  ability to
           record, process, summarize and report financial information; and

      b)   any fraud, whether or not material, that involves management or other
           employees who have a significant  role in the  registrant's  internal
           control over financial reporting;

      Date: November 12, 2003                    /s/ SCOTT L. TARRIFF
                                                 --------------------
                                                   Scott L. Tarriff
                                         President and Chief Executive Officer