EXHIBIT 31.1


                                  CERTIFICATION
            PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002


I,  Michael  D.  Becker,  President  and  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))  and internal
         control  over  financial  reporting  (as defined in Exchange  Act Rules
         13a-15(f) and 15d-15(f)) 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)       Designed such internal  control over financial  reporting,  or
                  caused such internal  control over  financial  reporting to be
                  designed  under  our   supervision,   to  provide   reasonable
                  assurance regarding the reliability of financial reporting and
                  the preparation of financial  statements for external purposes
                  in accordance with generally accepted accounting principles;

         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  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 (or persons  performing the equivalent
         functions):
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         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:   May 10, 2005                             Michael D. Becker, President
                                                  and Chief Executive Officer
                                                  (Principal Executive Officer)