Filed Pursuant to Rule 424(b)(3)
                                                under the Securities Act of
                                                1933, as amended
                                                (Registration Statement
                                                        No. 333-109344)


                               CYTOGEN CORPORATION

                Prospectus Supplement No. 1 dated January 3, 2005
                     to the Prospectus dated October 6, 2003

                        2,694,664 Shares of Common Stock
                                ($0.01 par value)


     The  information in this prospectus  supplement  supplements the prospectus
dated October 6, 2004 of Cytogen Corporation,  a Delaware corporation,  relating
to an aggregate of 2,694,664 shares of common stock,  $0.01 par value per share,
including  shares  of  our  common  stock  underlying  immediately   exercisable
warrants,  that may be sold or  otherwise  transferred  from time to time by the
stockholders  and  warrantholders  who  received  such  shares and  warrants  in
connection with our private offering of common stock and warrants consummated on
July 10, 2004, or by such other permitted pledgees, donees, transferees or other
permitted  successors  in interest that may receive such shares or warrants as a
gift,  pledge,  distribution  to members or partners  or other  non-sale-related
transfer.

     This prospectus  supplement  should be read in conjunction with, may not be
delivered or utilized without,  and is qualified by reference to, the prospectus
except to the  extent  that the  information  herein  contained  supplements  or
supersedes the information  contained in the prospectus.  Capitalized terms used
in this prospectus supplement and not otherwise defined herein have the meanings
specified in the prospectus.

                              SELLING STOCKHOLDERS

     Subsequent  to the  filing  of the  prospectus,  BayStar  Capital  II  L.P.
transferred  a total of 125,000  warrants to North Sound  Legacy  International,
Ltd., North Sound Legacy Fund LLC and North Sound Legacy Institutional Fund LLC.
None of the foregoing transferees were specifically named in the prospectus.

     The  following  table  lists  the  Selling   Stockholders   not  previously
specifically  identified  in the  prospectus as a Selling  Stockholder,  and the
number of  warrants  each such  Selling  Stockholder  beneficially  owns and may
exercise and sell pursuant to the prospectus  from time to time. The information
in  the  table  appearing  under  the  heading  "Selling  Stockholders"  in  the
prospectus is hereby amended by the information set forth below.

     This information was furnished to us by the listed Selling  Stockholders on
or before December 28, 2004. Because the Selling  Stockholders may, at any time,
acquire or dispose of shares of our common  stock  without  providing  notice of
such  transactions  to us, the table below may not reflect the exact  beneficial
ownership  of our common  stock  held by the  Selling  Stockholders  on the date
hereof.

     Beneficial ownership is determined in accordance with the rules of the SEC,
and includes voting or investment power with respect to shares. Shares of common
stock issuable under stock options and




warrants that are exercisable  within 60 days after December 28, 2004 are deemed
outstanding  for computing the  percentage  ownership of the person  holding the
options and warrants but are not deemed outstanding for computing the percentage
ownership  of  any  other  person.  Unless  otherwise  indicated  below,  to our
knowledge,  all persons named in the table have sole voting and investment power
with respect to their shares of common stock,  except to the extent authority is
shared by spouses  under  applicable  law.  The  inclusion of any shares in this
table does not  constitute an admission of  beneficial  ownership for the person
named below.



                                                                         Number of
                                         Beneficial Ownership of         Shares of          Beneficial Ownership of
                                        Selling Stockholder Prior       Common Stock       Selling Stockholder After
   Name of Selling Stockholder (1)             to Offering              Being Offered               Offering
-----------------------------------    ---------------------------    -----------------    --------------------------
                                        Number      Percentage (2)                          Number (3) Percentage (2)
-----------------------------------    --------     --------------    -----------------    ----------  --------------
                                                                                               
North Sound Legacy
International, Ltd. (4)............    181,053 (5)       1.2%             80,000 (9)       101,053 (9)        *

North Sound Legacy Fund
LLC (4)............................      8,487 (6)         *               3,750 (9)         4,737 (9)        *

North Sound Institutional Fund
LLC (4)............................     93,355 (7)         *              41,250 (9)        52,105 (9)        *

BayStar Capital II L.P.............          0 (8)         *                 0                  0             *


-----------------------------------
* Less than one percent.

(1)  None of the Selling  Stockholders  has held any position or office with, or
     has  otherwise  had  a  material  relationship  with,  us  or  any  of  our
     subsidiaries within the past three years.

(2)  Applicable  percentage  ownership is based on  15,488,933  shares of common
     stock outstanding as of December 28, 2004, plus any common stock equivalent
     or convertible  securities held or shares  beneficially  owned by each such
     holder.

(3)  We do not know  when or in what  amounts a  Selling  Stockholder  may offer
     shares for sale. The Selling  Stockholders might not sell any or all of the
     shares offered by this  prospectus.  Because the Selling  Stockholders  may
     offer all or some of the shares  pursuant  to this  offering,  and  because
     there are currently no  agreements,  arrangements  or  understandings  with
     respect to the sale of any of the shares,  we cannot estimate the number of
     shares that will be held by the Selling  Stockholders  after  completion of
     the offering.  However,  for purposes of this table,  we have assumed that,
     after  completion  of the  offering,  none of the  shares  covered  by this
     prospectus will be held by the Selling Stockholders.

(4)  North Sound  Capital LLC is the Managing  Member of North Sound Legacy Fund
     LLC, North Sound Legacy  Institutional Fund LLC, and the investment advisor
     of North Sound Legacy  International,  Ltd.  Thomas McAuley is the managing
     member of North Sound Capital LLC, and is the individual  with the power to
     vote and to direct the  disposition of all  securities  held by North Sound
     Legacy Fund LLC,  North Sound  Legacy  International,  Ltd. and North Sound
     Legacy Institutional Fund LLC.

(5)  Includes: (i) 101,053 shares issuable upon the exercise of warrants held by
     North Sound  Legacy  International,  Ltd.  which have an exercise  price of
     $6.91 per share and provide that such  warrants may not be exercised in the
     event  such  exercise  would  cause  the  holder's   beneficial   ownership
     percentage  to exceed  4.99%;  and (ii)  80,000  shares  issuable  upon the
     exercise of warrants held by North Sound Legacy  International  Ltd.  which
     have an exercise price of $10.97 per share and




     which are immediately  exercisable and may be automatically exercised under
     certain circumstances.

(6)  Includes:  (i) 4,737 shares  issuable upon the exercise of warrants held by
     North Sound Legacy Fund LLC which have an exercise price of $6.91 per share
     and  provide  that such  warrants  may not be  exercised  in the event such
     exercise would cause the holder's beneficial ownership percentage to exceed
     4.99%; and (ii) 3,750 shares issuable upon the exercise of warrants held by
     North  Sound  Legacy  Fund LLC which have an  exercise  price of $10.97 per
     share  and  which  are  immediately  exercisable  and may be  automatically
     exercised under certain circumstances.

(7)  Includes:  (i) 52,105 shares issuable upon the exercise of warrants held by
     North Sound  Institutional  Fund LLC which have an exercise  price of $6.91
     per share and provide that such  warrants may not be exercised in the event
     such exercise would cause the holder's beneficial  ownership  percentage to
     exceed 4.99%; and (ii) 41,250 shares issuable upon the exercise of warrants
     held by North  Sound  Institutional  Fund LLC having an  exercise  price of
     $10.97  per  share  and  which  are  immediately  exercisable  and  may  be
     automatically exercised under certain circumstances.

(8)  All of such 125,000 warrants previously held by BayStar Capital II L.P., as
     set forth in the prospectus,  were  transferred to North Sound, and are not
     included herein.

(9)  Such  amounts are  comprised  solely of shares of common  stock  underlying
     warrants.