EXHIBIT 31.1

                                  CERTIFICATION

I, Michael D. Becker,  Chief Executive Officer of Cytogen  Corporation,  certify
that:

1.       I  have  reviewed  this  Quarterly  Report  on  Form  10-Q  of  Cytogen
         Corporation;

2.       Based  on my  knowledge,  this  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 report;

3.       Based on my knowledge,  the financial  statements,  and other financial
         information  included in this  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 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 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 report is being prepared;
          b)   [Paragraph omitted in accordance with SEC transition instructions
               contained in SEC Release 34-47986];
          c)   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
          d)   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 (the registrant's  fourth
               fiscal  quarter  in  the  case  of an  annual  report)  that  has
               materially  affected,  or  is  reasonably  likely  to  materially
               affect,   the   registrant's   internal  control  over  financial
               reporting; and
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 (or persons  performing the equivalent
         functions):

          a)   All  significant  deficiencies  and  material  weaknesses  in the
               design or operation of internal control 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.


                                      /s/ Michael D. Becker
                                      --------------------------------------
Dated: August 14, 2003                Michael D. Becker, President and Chief
                                      Executive Officer
                                      (Principal Executive Officer)