SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                -----------------

                                    FORM 11-K

                                 ANNUAL REPORT
                           PURSUANT TO SECTION 15 (d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934


(Mark One)
[ X ]             ANNUAL REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES
                  EXCHANGE ACT OF 1934 [FEE REQUIRED]


                   For the fiscal year ended December 31, 2000

                                       OR

[   ]             TRANSITION REPORT PURSUANT TO SECTION 15 (d) OF THE
                  SECURITIES EXCHANGE ACT OF 1934 [NO FEE REQUIRED]


           For the transition period from ____________ to ____________


                        Commission File Number 000-14879


            A.  Full title of the plan and the address of the plan, if
                different from that of the issuer named below:


                         CYTOGEN RETIREMENT SAVINGS PLAN


            B.  Name of issuer of the securities held pursuant to the plan
                and the address of its principal executive office:

                               CYTOGEN CORPORATION
                          600 COLLEGE ROAD EAST CN-5308
                            PRINCETON, NJ 08540-5308
                                  (609)750-8200






                         CYTOGEN RETIREMENT SAVINGS PLAN
                   INDEX TO FINANCIAL STATEMENT AND SCHEDULES

                                DECEMBER 31, 2000




                                                                        Page No.
                                                                        --------
       Required Information....................................................2

       Report of Independent Public Accountants................................3

       Financial Statements:
          Statements of net assets available for Plan benefits
             As of December 31, 2000 and 1999..................................4
          Statement of changes in net assets available for Plan benefits
             For the year ended December 31, 2000..............................5

       Notes to financial statements
          As of December 31, 2000..............................................6

       Supplemental Schedules:
          Schedule H, Part IV, Item i - Schedule of assets
            held for investment purposes
             As of December 31, 2000..........................................11

       Schedule H, Part IV, Item j - Schedule of non-exempt transactions
             As of December 31, 2000..........................................12

       Schedule 27(b)-Schedule of loans or fixed income obligations
             As of December 31, 2000..........................................13

       Signature..............................................................14

       Exhibit 23 - Consent of Independent Accountants........................15


















                                      1



                              REQUIRED INFORMATION




1.   Financial  Statements and Schedules of the Cytogen  Retirement Savings Plan
     prepared in accordance  with the financial  reporting  requirements  of the
     Employee Retirement Income Security Act of 1974, as amended.


Exhibit 23.  Consent of Arthur Andersen, Independent Accountants










                                       2






Report of independent public accountants



To the Plan Administrator of
Cytogen Retirement Savings Plan:

We have audited the accompanying statements of net assets available for benefits
of Cytogen Retirement Savings Plan ("the Plan") as of December 31, 2000 and
1999, and the related statement of changes in net assets available for benefits,
and supplemental schedules, for the year ended December 31, 2000. These
financial statements and supplemental schedules are the responsibility of the
Plan's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States. Those standards require that we plan and perform the audit
to obtain reasonable assurance about whether the financial statements are free
of material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant estimates
made by management, as well as evaluating the overall financial statement
presentation. We believe that our audits provide a reasonable basis for our
opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the net assets available for benefits of the Plan as of
December 31, 2000 and 1999, and the changes in its net assets available for
benefits, and supplemental schedules, for the year ended December 31, 2000, in
conformity with accounting principles generally accepted in the United States.





                                                        /s/ Arthur Andersen, LLP
                                                       -------------------------


Philadelphia, Pennsylvania
     July 23, 2001



                                    3








Cytogen Retirement Savings Plan


Statements of net assets available for Plan benefits
As of December 31, 2000 and 1999



                                                       2000            1999
                                                  ------------     ------------
Assets:
  Investments                                     $ 7,486,678      $ 8,894,047
  Participant's contribution receivable                14,553           79,834
  Employer contribution receivable                     55,909            3,730
  Loans receivable                                          -              231
                                                  -----------      -----------
Net assets available for plan benefits            $ 7,557,140      $ 8,977,842
                                                  ===========      ===========






 The accompanying notes are an integral part of these financial statements.

                                       4







Cytogen Retirement Savings Plan


Statement of changes in net assets available for Plan benefits
For the year ended December 31, 2000




Net assets available for Plan benefits, beginning of year          $  8,977,842
Additions:
   Investment income-
     Interest and dividends                                             631,294
     Interest income from loans                                           2,117
                                                                   -------------
                                                                        633,411
                                                                   -------------
   Contributions-

     Participant                                                        310,314
     Employer                                                           112,496
     Rollovers                                                           21,568
                                                                   -------------
                                                                        444,378
                                                                   -------------
Total additions                                                       1,077,789
                                                                   -------------
Deductions:
   Net depreciation in fair value of investments                     (1,033,631)
   Benefits paid to participants                                     (1,464,860)
                                                                   -------------
Total deductions                                                     (2,498,491)
                                                                   -------------
Net decrease                                                         (1,420,702)
                                                                   -------------
Net assets available for Plan benefits, end of year                $  7,557,140
                                                                   =============


The accompanying notes are an integral part of this financial statement.

                                       5







          Cytogen Retirement Savings Plan

          Notes to financial statements
          As of December 31, 2000




          1. Description of the plan:

          Organization

          The Cytogen Retirement Savings Plan (the Plan) is a defined
          contribution  plan  for the  employees  of  Cytogen  Corporation  (the
          Employer or Company) that was  established  on December 15, 1986.  The
          Plan is governed by the provisions of the Employee  Retirement  Income
          Security Act of 1974  (ERISA),  as amended,  and is intended to comply
          with Sections 401(a) and 401(k) of the Internal Revenue Code (IRC).

          The   following   description   of  the  Plan  provides  only  general
          information. Participants should refer to the Plan document for a more
          complete description of the Plan's provisions.

          Effective September 1, 1999,  Massachusetts Financial Services Company
          replaced   Prudential   Mutual  Fund  Service,   Inc.  as  the  Plan's
          Recordkeeper and Investment Manager.

          Eligibility

          Each employee shall become eligible to participate  within the Plan as
          of the date  when the  employee  attains  the age of 21 years  and has
          completed one month of service.

          Administration

          The Employer  designates a person or persons to serve as administrator
          under the Plan,  who shall perform all such duties as are necessary to
          operate,  administer,  and manage the Plan. The expenses  necessary to
          administer  the  Plan  shall  be  borne  by  the  Employer,  including
          necessary professional assistance.

          Contributions

          Each  active  participant  may enter  into a written  salary  deferral
          agreement  with the  Employer in which the employee may elect to defer
          an amount from 1 percent to 15 percent of his or her  compensation and
          the Employer shall make a matching  contribution in an amount equal to
          50 percent of the employee contribution, not to exceed limitations set
          forth by the Plan.  The  Employer  may also  make an  annual  Employer
          discretionary  contribution  under  the  Plan in an  amount  that  the
          Employer's  Board of  Directors  shall  determine by  resolution.  The
          allocation  of this  discretionary  contribution  shall be made in the
          proportion that the compensation  paid to each participant  during the
          Plan year  bears to the  compensation  paid to all such  participants,
          subject to limitation set forth by the Plan.

          The Plan also  permits  the  rollover of cash  transferred  from other
          employee benefit plans which are qualified under the IRC. Rollovers of
          cash are  included  as part of asset  additions  in the  statement  of
          changes  in net  assets  available  for  benefits.  For the year ended
          December 31, 2000, rollovers of cash amounted to $21,568.



                                        6

          Vesting and forfeitures

          A participant's  interest in the Employer matching contribution is 100
          percent vested upon the contribution.  A participant's interest in the
          Employer's  discretionary  contributions  vests  over  four  years  of
          service,  at which time it becomes 100 percent vested.  Vesting credit
          shall be given for each year of  service,  except  plan  years  during
          which a participant  did not complete at least 1,000 hours of service.
          If a participant  terminates employment and is not 100 percent vested,
          the nonvested portion of the participant's  account shall be placed in
          a separate  account  and will become a  forfeiture  upon the date such
          terminated  participant  incurs a  one-year  break in  service.  These
          forfeitures  shall be used by the  Employer  to reduce the  Employer's
          contribution.

          Distributions/Benefits

          A  participant  who  attains  the normal  retirement  age shall have a
          vesting percentage of 100 percent.  If a participant  retires from the
          active service of the Employer on the normal  retirement date, then he
          or she  shall  receive a  distribution  of the  entire  value of their
          participant account. A participant who retires from the service of the
          Employer on account of disability  shall have a vesting  percentage of
          100 percent and shall  receive a  distribution  of the entire value of
          their participant account.

          Participant loans

          All  participants  in  the  Plan  may  obtain  a loan  secured  by the
          participant's  account balance. The amount of all outstanding loans to
          a participant  may not exceed 50 percent of the  participant's  vested
          account  balance.  The  loans are made at a rate  equivalent  to rates
          charged by a professional lender in a similar circumstance.  Loans are
          repaid  in no more  than  five  years,  except  if the loan is for the
          purchase of the  participant's  primary  residence,  in which case the
          repayment period may exceed five years.

          Investment options

          Prudential  Mutual  Fund  Services,  Inc.  was the  Plan's  investment
          manager  from  January 1, 1999  through  August 31,  1999.  The Plan's
          investment  options under the  management  of  Prudential  Mutual Fund
          Services, Inc. were as following:

                Fund                                    Objective
-----------------------------------     ----------------------------------------
Money Market Funds                      Invests in a broad range of money market
                                        instruments.  Includes Government
                                        Securities Trust, Special and Privileged
                                        Funds.

  Prudential Equity Fund A              Invests in stocks, bonds and money
  Prudential Equity Fund B              market investments.
  Fidelity Equity Income Fund T
  Prudential Balanced Fund A
  Prudential Balanced Fund B
  Fidelity Growth Opportunity Fund T

  Prudential Government Income Fund A   Invests in a broad range of fixed income
  Prudential Government Income Fund B   securities.

  Putnam Voyager Fund A                 Invests in stocks and money market
  Putnam International Growth Fund A    instruments.
  AIM Constellation Fund A

  Prudential Jennison Growth Fund       Invests in growth stocks.



                                       7

          Effective as of September 1, 1999,  Massachusetts  Financial  Services
          Company (the Trustee) was the Plan's  investment  manager.  The Plan's
          investment  options under the  management of  Massachusetts  Financial
          Services Company include the following:


                Fund                                    Objective
-------------------------------------     --------------------------------------
MFS Emerging Growth Fund                  Invests in emerging growth companies,
                                          foreign and emerging market
                                          securities, and derivative securities.

MFS Money Market Fund                     Invests in a broad range of money
                                          market instruments.

Massachusetts Investor Trust              Invests in stocks, foreign and
                                          emerging market securities, and
                                          derivative securities.

Massachusetts Investor Growth Stock Fund  Invests in long-term growth companies,
                                          foreign and emerging market
                                          securities, and derivative securities.

MFS Research Fund                         Invests in a broad range of stocks.

MFS Total Return Fund                     Invests in fixed-income securities,
                                          stocks, and derivative securities.

MFS High Income Fund                      Invests in high yield corporate bonds,
                                          high yield securities, and foreign and
                                          emerging market securities.

MFS Capital Opportunities Fund            Invests in moderate growth companies,
                                          foreign and emerging market
                                          securities, and derivative securities.

MFS Government Securities Fund            Invests in fixed-income government
                                          securities and derivatives securities.

MFS Global Equity Fund                    Invests in common stocks and
                                          equivalents, foreign and emerging
                                          market securities, and derivative
                                          securities.

MFS Fixed Fund                            Invests in stable-value investment
                                          contracts.

          Termination

          As  of a  participant's  termination  of  employment,  they  shall  be
          entitled to receive a  distribution  of their entire vested  interest.
          Such distribution shall be further subject to terms and conditions set
          forth by the Plan.

          2. Summary of significant accounting policies:

          Basis of accounting

          The Plan is  subject  to the  provisions  of the  Employee  Retirement
          Income  Security Act of 1974,  as amended  (ERISA).  The  accompanying
          financial  statements  have  been  prepared  on the  accrual  basis of
          accounting,  except for distributions that are accounted for on a cash
          basis in accordance with the AICPA Audit and Accounting Guide entitled
          "Audits of Employee  Benefit Plans."  Investments are stated at market
          value.


                                       8

          Use of estimates

          The  preparation of financial  statements in conformity with generally
          accepted   accounting   principles  in  the  United  States   requires
          management to make estimates and assumptions that affect the financial
          statements and the related  disclosures  during the reporting  period.
          Actual results could differ from those estimates.

          New accounting pronouncements

          The  Accounting  Standards  Executive  Committee  issued  Statement of
          Position  99-3   Accounting  for  the  Reporting  of  Certain  Defined
          Contribution Plan Investments and Other Disclosure Matters (SOP) which
          eliminates  the  requirements  for  a  defined  contribution  plan  to
          disclose  participant-directed  investment programs. The SOP was early
          adopted for the 1999 financial statements.

          Valuation of investments

          Investments  represent  units in a  series  of  funds  managed  by the
          investment  manager.  The Plan's investment funds are stated at market
          value, as determined based on market quotes of the underlying assets.

          Plan expenses

          All administrative costs associated with the operation of the Plan are
          paid by the Employer in accordance with the terms of the Plan.

          3. Investments:

          The following  table presents the current values of individual  assets
          that  represent  5 percent or more of the Plan's net assets  available
          for benefits as of December 31, 2000 and 1999 as follows:

Description/Issuer of Investment                     2000              1999
-------------------------------------------      -----------       -----------
MFS Emerging Growth Fund                         $   808,246       $ 1,112,779
Massachusetts Investor Trust                         620,564           487,963
Massachusetts Investor Growth Stock Fund           2,260,178         2,864,003
MFS Research Fund                                    689,687           927,205
MFS Capital Opportunities Fund                       897,482         1,091,311
MFS Government Securities Fund                       965,414         1,142,123
MFS Global Equity Fund                               398,032           554,073
MFS Fixed Fund                                       604,113           519,753


          4. Tax status:

          The trust  established  under the Plan is  qualified  under the IRC as
          exempt from federal  income  taxes.  The Plan has received a favorable
          determination  letter  from the IRS but has not been  updated  for the
          most recent plan amendment.  However,  the plan  administrator and the
          Plan's tax counsel  believe  that the Plan is  currently  designed and
          being operated in compliance  with the applicable  requirements of the
          IRC.  Therefore,  they  believe  that the Plan was  qualified  and the
          related trust was tax-exempt as of the financial statement date.



                                       9

          5. Plan termination:

          Although it has not expressed any intent to do so, the Company has the
          right under the Plan to discontinue its  contributions  at anytime and
          to terminate  the Plan,  subject to the  provisions  of ERISA.  In the
          event of termination,  distributions shall be subject to the terms and
          conditions set forth by the Plan.

          6. Distributions/benefits paid to participants:

          Distributions/benefits  paid to  participants  are generally made on a
          monthly  basis for those  requests  processed in the  previous  month.
          There were no distributions/benefits payable to the participants as of
          December 31, 2000.


                                       10



          Cytogen Retirement Savings Plan


          Schedule H, Part IV, Item i - Schedule of assets held
          for investment purposes
          As of December 31, 2000



                                                                        Market
               Description of investment                                 value
---------------------------------------------------------            -----------

MFS Emerging Growth Fund                                             $   808,246
MFS Money Market Fund                                                     40,431
Massachusetts Investor Trust                                             620,564
Massachusetts Investor Growth Stock Fund                               2,260,178
MFS Research Fund                                                        689,687
MFS Total Return Fund                                                    164,373
MFS High Income Fund                                                      37,746
MFS Capital Opportunities Fund                                           897,482
MFS Government Securities Fund                                           965,414
MFS Global Equity Fund                                                   398,032
MFS Fixed Fund                                                           604,113
*Participant Loans
   (interest rates ranging from 6 percent to 9.5 percent)                    412
                                                                     -----------
Total                                                                $ 7,486,678
                                                                     ===========
  * Represents a party-in-interest.





                                       11







          Cytogen Retirement Savings Plan


          Schedule H, Part IV, Item j - Schedule of non-exempt transactions
          As of December 31, 2000




                                                                       Amount
Identity of party involved         Description of transaction         of loan
--------------------------      --------------------------------      -------
Cytogen Corporation             Deemed interest-free loan to the      $15,431
                                Company dated February 25, 2000,
                                maturity April 14, 2000

Cytogen Corporation             Deferred interest-free loan to the    $14,782
                                Company dated April 22, 2000,
                                maturity April 27, 2000



                                       12



                                     Cytogen Retirement Savings Plan

                        ITEM 27(b)-SCHEDULE OF LOANS OR FIXED INCOME OBLIGATIONS

                                         AS OF DECEMBER 31, 2000





                          Original     Amount Received During      Unpaid
Identity and Address       Amount       the Reporting Year        Balance at      Description         Amount Overdue
                                       ----------------------                                      --------------------
     of Obligor           of Loan      Principal     Interest    End of year        of Loan        Principal   Interest
--------------------     ---------     ---------     --------    -----------      -----------      ---------   --------

                                                                                            
James Aiken                $3,000         $0            $0          $2,595       8.5% interest,      $2,243      $  352
1050 George St. Apt 19H                                                        Beginning February
New Brunswick, NJ 08901                                                         23, 1998; 130 bi-
                                                                                 weekly payments
                                                                                maturing March 12,
                                                                                       2003

Thomas Balla               $8,880         $0            $0          $9,605       9.25% interest,     $7,054      $2,551
14 Petunia Drive                                                               Beginning April 28,
North Brunswick, NJ 08902                                                      1996; 260 bi-weekly
                                                                                payments maturing
                                                                                  April 15, 2006





                                                  13



                                    SIGNATURE



THE PLAN

Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the Plan
has duly caused this annual report to be signed on its behalf by the undersigned
hereunto duly authorized.

                                       CYTOGEN RETIREMENT SAVINGS PLAN


                                     By: Cytogen Corporation, Plan Administrator


Date:     July 26, 2001              By:    /s/ Catherine M. Verna
       ------------------------          ---------------------------------------
                                         Catherine M. Verna
                                         Vice President and General Counsel








                                      14