EXHIBIT 10.3

                                                                       EXHIBIT B


                          REGISTRATION RIGHTS AGREEMENT


                  This Registration  Rights Agreement (this "Agreement") is made
and  entered  into as of June 6,  2003,  by and  among  Cytogen  Corporation,  a
Delaware corporation (the "Company"), and the investors signatory hereto (each a
"Purchaser" and collectively, the "Purchasers").

         This Agreement is made pursuant to the Securities  Purchase Agreement,
dated as of the date hereof among the Company and the Purchasers  (the "Purchase
Agreement").

         The Company and the Purchasers hereby agree as follows:

     1.  Definitions.  Capitalized  terms used and not otherwise  defined herein
that are defined in the Purchase  Agreement  shall have the meanings  given such
terms in the Purchase Agreement. As used in this Agreement,  the following terms
shall have the following meanings:

          "Effectiveness  Date" means, with respect to the initial  Registration
     Statement required to be filed hereunder,  the earlier of (a) 90th calendar
     day  following  the Closing  Date (120 days in the event of a review by the
     Commission or in the event the Commission  delays the  effectiveness of the
     Registration  Statement  due  to a  review  of  the  Company's  outstanding
     confidentiality  treatment  applications)  and (b) the  fifth  Trading  Day
     following the date on which the Company is notified by the Commission  that
     such Registration Statement will not be reviewed or is no longer subject to
     further review and comments and with respect to any additional Registration
     Statements  required  pursuant to Section 2(c), the earlier of (x) the 60th
     calendar  day  following  the date on which the  Company  first  knows,  or
     reasonably should have known, that such additional  Registration  Statement
     is required  hereunder  and (y) the fifth Trading Day following the date on
     which the  Company is  notified by the  Commission  that such  Registration
     Statement  will not be reviewed or is no longer  subject to further  review
     and comments.

          "Effectiveness  Period"  shall have the  meaning  set forth in Section
     2(a).

          "Filing  Date"  means,  with  respect  to  the  initial   Registration
     Statement  required to be filed hereunder,  the 30th calendar day following
     the  Closing  Date  and,  with  respect  to  any  additional   Registration
     Statements  which  may be  required  pursuant  to  Section  2(c),  the 30th
     calendar  day  following  the date on which the  Company  first  knows,  or
     reasonably should have known that such additional Registration Statement is
     required hereunder.

          "Holder" or "Holders" means the holder or holders, as the case may be,
     from time to time of Registrable Securities.

          "Indemnified Party" shall have the meaning set forth in Section 5(c).


                                       1


          "Indemnifying Party" shall have the meaning set forth in Section 5(c).

          "Losses" shall have the meaning set forth in Section 5(a).

          "Proceeding" means an action, claim, suit, investigation or proceeding
     (including,  without  limitation,  an investigation or partial  proceeding,
     such as a deposition), whether commenced or threatened.

          "Prospectus" means the prospectus included in a Registration Statement
     (including,  without limitation, a prospectus that includes any information
     previously  omitted  from  a  prospectus  filed  as  part  of an  effective
     registration  statement in reliance  upon Rule 430A  promulgated  under the
     Securities  Act), as amended or supplemented by any prospectus  supplement,
     with respect to the terms of the offering of any portion of the Registrable
     Securities  covered by a Registration  Statement,  and all other amendments
     and supplements to the Prospectus, including post-effective amendments, and
     all material  incorporated  by reference  or deemed to be  incorporated  by
     reference in such Prospectus.

          "Registrable   Securities"   means  the  Shares,   together  with  any
     securities  issued or  issuable  upon any stock  split,  dividend  or other
     distribution,  recapitalization  or  similar  event  with  respect  to  the
     foregoing.

          "Registration  Statement" means a Registration  Statements required to
     be filed hereunder, including (in each case) the Prospectus, amendments and
     supplements to such  registration  statement or Prospectus,  including pre-
     and  post-effective  amendments,  all  exhibits  thereto,  and all material
     incorporated by reference or deemed to be incorporated by reference in such
     registration statement.

          "Rule 415" means Rule 415  promulgated by the  Commission  pursuant to
     the  Securities  Act, as such Rule may be amended from time to time, or any
     similar  rule or  regulation  hereafter  adopted by the  Commission  having
     substantially the same effect as such Rule.

          "Rule 424" means Rule 424  promulgated by the  Commission  pursuant to
     the  Securities  Act, as such Rule may be amended from time to time, or any
     similar  rule or  regulation  hereafter  adopted by the  Commission  having
     substantially the same effect as such Rule.

          "Securities Act" means the Securities Act of 1933, as amended.

          "Shares" solely for the purpose of this Agreement means the Shares (as
     defined  in the  Purchase  Agreement)  together  with  the  Warrant  Shares
     issuable upon exercise of the Warrants.

     2. Registration.

          (a) On or prior to each Filing  Date,  the Company  shall  prepare and
     file with the  Commission a Registration  Statement  covering the resale of
     100%  of  the  Registrable  Securities  for an  offering  to be  made  on a
     continuous  basis pursuant to Rule 415. A Registration  Statement  required

                                       2


     hereunder  shall be on Form S-3 (except if the Company is not then eligible
     to register  for resale the  Registrable  Securities  on Form S-3, in which
     case such registration  shall be on another  appropriate form in accordance
     herewith).  Each Registration  Statement  required  hereunder shall contain
     (except if otherwise  directed by the  Holders) the "Plan of  Distribution"
     attached  hereto as Annex A. The  Company  shall  cause  such  Registration
     Statement to become effective and remain effective as provided herein.  The
     Company  shall  use its  commercially  reasonable  efforts  to  cause  each
     Registration Statement to be declared effective under the Securities Act as
     promptly as possible after the filing  thereof,  but in any event not later
     than the  Effectiveness  Date,  and shall use its  commercially  reasonable
     efforts to keep such Registration  Statement  continuously  effective under
     the  Securities  Act until the date which is two years  after the date that
     such Registration Statement is declared effective by the Commission or such
     earlier date when all Registrable  Securities  covered by such Registration
     Statement  have  been  sold  or may be  sold  without  volume  restrictions
     pursuant  to Rule  144(k)  as  determined  by the  counsel  to the  Company
     pursuant  to a  written  opinion  letter  to  such  effect,  addressed  and
     acceptable to the Company's  transfer  agent and the affected  Holders (the
     "Effectiveness Period").

     (b) If: (i) a Registration Statement is not filed on or prior to its Filing
     Date (if the Company files a Registration  Statement  without affording the
     Holder the  opportunity  to review and  comment on the same as  required by
     Section 3(a), the Company shall not be deemed to have satisfied this clause
     (i)), or (ii) the Company  fails to file with the  Commission a request for
     acceleration in accordance  with Rule 461 promulgated  under the Securities
     Act,  within  five  Trading  Days of the date that the  Company is notified
     (orally or in  writing,  whichever  is earlier)  by the  Commission  that a
     Registration  Statement  will not be  "reviewed," or not subject to further
     review,  or (iii)  prior to the date when such  Registration  Statement  is
     first  declared  effective by the  Commission,  the Company fails to file a
     pre-effective  amendment and otherwise  respond in writing to comments made
     by the  Commission  in respect of such  Registration  Statement  within ten
     Trading Days after the receipt of comments by or notice from the Commission
     that such amendment is required in order for a Registration Statement to be
     declared effective,  or (iv) a Registration  Statement filed or required to
     be filed hereunder is not declared effective by the Commission on or before
     the  Effectiveness  Date,  or (v) after a  Registration  Statement is first
     declared  effective by the  Commission,  it ceases for any reason to remain
     continuously  effective as to all  Registrable  Securities  for which it is
     required to be  effective,  or the Holders are not permitted to utilize the
     Prospectus therein to resell such Registrable  Securities,  for in any such
     cases  ten  Trading  Days  (which  need  not be  consecutive  days)  in the
     aggregate  during any  12-month  period (any such  failure or breach  being
     referred to as an "Event,"  and for purposes of clause (i) or (iv) the date
     on which such Event  occurs,  or for  purposes  of clause  (ii) the date on
     which such five Trading Day period is exceeded,  or for purposes of clauses
     (iii) the date  which  such ten  Trading  Day  period is  exceeded,  or for
     purposes  of clause  (v) the date on which such ten  Trading  Day period is
     exceeded being referred to as "Event Date"),  then in addition to any other
     rights the Holders may have hereunder or under  applicable law: (x) on each
     such Event Date the Company  shall pay to each Holder an amount in cash, as
     liquidated  damages  and not as a  penalty,  equal  to 2% of the  aggregate
     purchase price paid by such Holder pursuant to the Purchase Agreement for

                                       3


     any  Registrable  Securities  then  held  by such  Holder;  and (y) on each
     monthly  anniversary of each such Event Date (if the applicable Event shall
     not have been cured by such date) until the applicable  Event is cured, the
     Company shall pay to each Holder an amount in cash,  as liquidated  damages
     and not as a penalty,  equal to 2% of the aggregate  purchase price paid by
     such  Holder  pursuant  to  the  Purchase  Agreement  for  any  Registrable
     Securities  then  held by such  Holder.  If the  Company  fails  to pay any
     liquidated damages pursuant to this Section in full within seven days after
     the date  payable,  the Company will pay interest  thereon at a rate of 18%
     per annum (or such lesser  maximum  amount that is  permitted to be paid by
     applicable law) to the Holder, accruing daily from the date such liquidated
     damages are due until such  amounts,  plus all such interest  thereon,  are
     paid in full.

          (c) If during the  Effectiveness  Period,  the  number of  Registrable
     Securities at any time exceeds 100% of the number of shares of Common Stock
     then registered in a Registration Statement, then the Company shall file as
     soon as  reasonably  practicable  but in any case  prior to the  applicable
     Filing Date, an additional Registration Statement covering the resale of by
     the  Holders  of not  less  than  100% of the  number  of such  Registrable
     Securities.

     3. Registration Procedures

     In connection with the Company's registration  obligations  hereunder,  the
Company shall:

          (a) Not  less  than  three  Trading  Days  prior  to the  filing  of a
     Registration  Statement  or any  related  Prospectus  or any  amendment  or
     supplement thereto, the Company shall, (i) furnish to the Holders copies of
     all such documents proposed to be filed (including  documents  incorporated
     or deemed incorporated by reference to the extent requested by such Person)
     which  documents  will be subject to the review of such  Holders,  and (ii)
     cause its officers and directors,  counsel and independent certified public
     accountants  to respond to such  inquiries  as shall be  necessary,  in the
     reasonable   opinion  of   respective   counsel  to  conduct  a  reasonable
     investigation  within the meaning of the Securities  Act. The Company shall
     not file a Registration  Statement or any such Prospectus or any amendments
     or  supplements  thereto  to  which  the  Holders  of  a  majority  of  the
     Registrable Securities shall reasonably object.

          (b)  (i)  Prepare  and  file  with  the  Commission  such  amendments,
     including  post-effective  amendments,  to a Registration Statement and the
     Prospectus  used in  connection  therewith  as may be  necessary  to keep a
     Registration   Statement   continuously  effective  as  to  the  applicable
     Registrable  Securities for the  Effectiveness  Period and prepare and file
     with the Commission  such  additional  Registration  Statements in order to
     register  for  resale  under  the  Securities  Act  all of the  Registrable
     Securities; (ii) cause the related Prospectus to be amended or supplemented
     by any required Prospectus supplement, and as so supplemented or amended to
     be filed  pursuant to Rule 424;  (iii)  respond as  promptly as  reasonably
     possible,  and in any event within  fifteen days, to any comments  received
     from  the  Commission  with  respect  to a  Registration  Statement  or any
     amendment  thereto and, as promptly as reasonably  possible,  upon request,
     provide the Holders true and complete copies of all correspondence from and

                                       4


     to the Commission relating to such Registration Statement;  and (iv) comply
     in all material  respects with the provisions of the Securities Act and the
     Exchange Act with respect to the disposition of all Registrable  Securities
     covered  by a  Registration  Statement  during  the  applicable  period  in
     accordance with the intended  methods of disposition by the Holders thereof
     set forth in a Registration  Statement as so amended or in such  Prospectus
     as so supplemented.

          (c)  Notify  the  Holders  of  Registrable  Securities  to be  sold as
     promptly as reasonably possible (and, in the case of (i)(A) below, not less
     than three Trading Days prior to such filing) and (if requested by any such
     Person)  confirm such notice in writing  promptly  following the day (i)(A)
     when a Prospectus or any Prospectus supplement or post-effective  amendment
     to a  Registration  Statement  is  proposed  to  be  filed;  (B)  when  the
     Commission  notifies  the  Company  whether  there will be a "review"  of a
     Registration  Statement and whenever the Commission  comments in writing on
     such  Registration  Statement (the Company shall upon request  provide true
     and complete  copies thereof and all written  responses  thereto to each of
     the  Holders);  and (C) with  respect to a  Registration  Statement  or any
     post-effective  amendment,  when the same has become effective; (ii) of any
     request  by the  Commission  or any  other  Federal  or state  governmental
     authority during the period of  effectiveness  of a Registration  Statement
     for amendments or supplements to a Registration  Statement or Prospectus or
     for additional information;  (iii) of the issuance by the Commission or any
     other federal or state governmental  authority of any stop order suspending
     the  effectiveness of a Registration  Statement  covering any or all of the
     Registrable  Securities  or the  initiation  of any  Proceedings  for  that
     purpose;  (iv) of the  receipt  by the  Company  of any  notification  with
     respect  to  the  suspension  of  the   qualification   or  exemption  from
     qualification  of  any  of  the  Registrable  Securities  for  sale  in any
     jurisdiction,  or the  initiation or threatening of any Proceeding for such
     purpose;  and (v) of the  occurrence  of any event or  passage of time that
     makes  the  financial  statements  included  in  a  Registration  Statement
     ineligible for inclusion therein or any statement made in such Registration
     Statement  or  Prospectus  or any  document  incorporated  or  deemed to be
     incorporated  therein by reference  untrue in any material  respect or that
     requires any revisions to such Registration Statement,  Prospectus or other
     documents  so  that,  in  the  case  of a  Registration  Statement  or  the
     Prospectus, as the case may be, it will not contain any untrue statement of
     a material  fact or omit to state any material  fact  required to be stated
     therein  or  necessary  to make  the  statements  therein,  in light of the
     circumstances under which they were made, not misleading.

          (d) Use its commercially  reasonable efforts to avoid the issuance of,
     or, if  issued,  obtain  the  withdrawal  of (i) any order  suspending  the
     effectiveness  of a Registration  Statement,  or (ii) any suspension of the
     qualification  (or exemption from  qualification) of any of the Registrable
     Securities  for  sale  in any  jurisdiction,  at the  earliest  practicable
     moment.

          (e) Furnish to each Holder,  without  charge,  at least one  conformed
     copy of each Registration  Statement and each amendment thereto,  including
     financial statements and schedules, all documents incorporated or deemed to
     be  incorporated  therein  by  reference  to the extent  requested  by such
     Person,  and all exhibits to the extent requested by such Person (including

                                       5


     those previously furnished or incorporated by reference) promptly after the
     filing of such documents with the Commission.

          (f) Promptly deliver to each Holder, without charge, as many copies of
     the Prospectus or Prospectuses (including each form of prospectus) and each
     amendment or supplement thereto as such Persons may reasonably request. The
     Company hereby consents to the use of such Prospectus and each amendment or
     supplement  thereto by each of the selling  Holders in connection  with the
     offering and sale of the Registrable  Securities covered by such Prospectus
     and any amendment or supplement thereto.

          (g) Prior to any public  offering of Registrable  Securities,  use its
     commercially  reasonable  efforts to register or qualify or cooperate  with
     the selling  Holders in connection with the  registration or  qualification
     (or exemption from such  registration or qualification) of such Registrable
     Securities for offer and sale under the securities or Blue Sky laws of such
     jurisdictions within the United States as any Holder reasonably requests in
     writing,  to keep each such  registration  or  qualification  (or exemption
     therefrom)  effective during the Effectiveness Period and to do any and all
     other  acts or things  reasonably  necessary  or  advisable  to enable  the
     disposition in such jurisdictions of the Registrable  Securities covered by
     a Registration Statement;  provided, that the Company shall not be required
     to -------- qualify  generally to do business in any jurisdiction  where it
     is not then so  qualified,  subject the Company to any  material tax in any
     such jurisdiction where it is not then so subject or file a general consent
     to service of process in any such jurisdiction.

          (h) Cooperate  with the Holders to facilitate  the timely  preparation
     and delivery of  certificates  representing  Registrable  Securities  to be
     delivered  to a  transferee  pursuant to a  Registration  Statement,  which
     certificates  shall  be  free,  to the  extent  permitted  by the  Purchase
     Agreement,  of all  restrictive  legends,  and to enable  such  Registrable
     Securities to be in such  denominations and registered in such names as any
     such Holders may request.

          (i) Upon the occurrence of any event  contemplated by Section 3(c)(v),
     as promptly as  reasonably  possible,  prepare a supplement  or  amendment,
     including a  post-effective  amendment,  to a  Registration  Statement or a
     supplement to the related Prospectus or any document incorporated or deemed
     to be  incorporated  therein  by  reference,  and file any  other  required
     document  so that,  as  thereafter  delivered,  neither  such  Registration
     Statement  nor such  Prospectus  will  contain  an  untrue  statement  of a
     material  fact or omit to  state a  material  fact  required  to be  stated
     therein  or  necessary  to make  the  statements  therein,  in light of the
     circumstances under which they were made, not misleading.

          (j)  Comply  with  all  applicable   rules  and   regulations  of  the
     Commission.

          (k) The  Company  may require  each  selling  Holder to furnish to the
     Company a certified  statement  as to the number of shares of Common  Stock
     beneficially owned by such Holder and, if requested by the Commission,  the
     controlling person thereof.

                                       6


     4. Registration Expenses. All fees and expenses incident to the performance
of or  compliance  with  this  Agreement  by the  Company  shall be borne by the
Company  whether  or not any  Registrable  Securities  are  sold  pursuant  to a
Registration  Statement.  The fees and  expenses  referred  to in the  foregoing
sentence shall include, without limitation, (i) all registration and filing fees
(including,  without  limitation,  fees and expenses (A) with respect to filings
required  to be made with the Trading  Market on which the Common  Stock is then
listed for trading,  and (B) in compliance with applicable  state  securities or
Blue Sky laws), (ii) printing expenses (including, without limitation,  expenses
of printing certificates for Registrable Securities and of printing prospectuses
if the  printing of  prospectuses  is  reasonably  requested by the holders of a
majority of the Registrable  Securities  included in a Registration  Statement),
(iii) messenger, telephone and delivery expenses, (iv) fees and disbursements of
counsel for the Company, (v) Securities Act liability insurance,  if the Company
so desires  such  insurance,  and (vi) fees and  expenses  of all other  Persons
retained by the Company in connection with the  consummation of the transactions
contemplated  by this Agreement.  In addition,  the Company shall be responsible
for all of its internal expenses incurred in connection with the consummation of
the transactions contemplated by this Agreement (including,  without limitation,
all salaries and expenses of its  officers  and  employees  performing  legal or
accounting  duties),  the expense of any annual  audit and the fees and expenses
incurred in  connection  with the listing of the  Registrable  Securities on any
securities exchange as required hereunder.

     5. Indemnification

          (a) Indemnification by the Company. The Company shall, notwithstanding
     any termination of this Agreement, indemnify and hold harmless each Holder,
     the officers,  directors, agents and employees of each of them, each Person
     who  controls  any such  Holder  (within  the  meaning of Section 15 of the
     Securities  Act or  Section  20 of the  Exchange  Act)  and  the  officers,
     directors,  agents and employees of each such  controlling  Person,  to the
     fullest  extent  permitted by applicable  law, from and against any and all
     losses, claims, damages, liabilities, costs (including, without limitation,
     reasonable  attorneys'  fees) and  expenses  (collectively,  "Losses"),  as
     incurred,  arising  out of or  relating  to any  untrue or  alleged  untrue
     statement of a material fact  contained in a  Registration  Statement,  any
     Prospectus  or any form of  prospectus  or in any  amendment or  supplement
     thereto or in any preliminary prospectus,  or arising out of or relating to
     any omission or alleged  omission of a material  fact required to be stated
     therein or  necessary  to make the  statements  therein (in the case of any
     Prospectus or form of prospectus  or  supplement  thereto,  in light of the
     circumstances  under  which they were made) not  misleading,  except to the
     extent,  but  only to the  extent,  that  (1)  such  untrue  statements  or
     omissions are based solely upon information regarding such Holder furnished
     in writing to the Company by such Holder  expressly for use therein,  or to
     the extent that such  information  relates to such Holder or such  Holder's
     proposed method of distribution of Registrable  Securities and was reviewed
     and  expressly  approved in writing by such Holder  expressly  for use in a
     Registration  Statement,  such  Prospectus or such form of Prospectus or in
     any amendment or supplement  thereto (it being  understood  that the Holder
     has  approved  Annex A hereto  for this  purpose)  or (2) in the case of an
     occurrence of an event of the type specified in Section  3(c)(ii)-(v),  the
     use by such Holder of an outdated or defective Prospectus after the Company
     has  notified  such Holder in writing  that the  Prospectus  is outdated or
     defective   and  prior  to  the  receipt  by  such  Holder  of  the  Advice

                                       7


     contemplated in Section 6(d). The Company shall notify the Holders promptly
     of the  institution,  threat or  assertion of any  Proceeding  of which the
     Company is aware in connection with the  transactions  contemplated by this
     Agreement.

          (b) Indemnification by Holders.  Each Holder shall,  severally and not
     jointly, indemnify and hold harmless the Company, its directors,  officers,
     agents and  employees,  each Person who  controls  the Company  (within the
     meaning of Section 15 of the  Securities Act and Section 20 of the Exchange
     Act), and the directors,  officers, agents or employees of such controlling
     Persons,  to the fullest  extent  permitted  by  applicable  law,  from and
     against all Losses,  as incurred,  arising out of or based solely upon: (x)
     such Holder's failure to comply with the prospectus  delivery  requirements
     of the Securities  Act or (y) any untrue or alleged  untrue  statement of a
     material fact contained in any Registration Statement,  any Prospectus,  or
     any form of prospectus, or in any amendment or supplement thereto or in any
     preliminary  prospectus,  or arising out of or relating to any  omission or
     alleged  omission  of a  material  fact  required  to be stated  therein or
     necessary to make the statements  therein not misleading (i) to the extent,
     but only to the extent, that such untrue statement or omission is contained
     in any  information  so  furnished in writing by such Holder to the Company
     specifically  for  inclusion  in  such   Registration   Statement  or  such
     Prospectus  or (ii) to the  extent  that  (1)  such  untrue  statements  or
     omissions are based solely upon information regarding such Holder furnished
     in writing to the Company by such Holder  expressly for use therein,  or to
     the extent that such  information  relates to such Holder or such  Holder's
     proposed method of distribution of Registrable  Securities and was reviewed
     and  expressly  approved in writing by such Holder  expressly  for use in a
     Registration  Statement (it being  understood  that the Holder has approved
     Annex  A  hereto  for  this  purpose),  such  Prospectus  or  such  form of
     Prospectus or in any amendment or supplement  thereto or (2) in the case of
     an  occurrence of an event of the type  specified in Section  3(c)(ii)-(v),
     the use by such  Holder of an outdated or  defective  Prospectus  after the
     Company has notified such Holder in writing that the Prospectus is outdated
     or  defective  and  prior  to the  receipt  by such  Holder  of the  Advice
     contemplated  in  Section  6(d).  In no event  shall the  liability  of any
     selling Holder hereunder be greater in amount than the dollar amount of the
     net  proceeds  received  by such  Holder  upon the sale of the  Registrable
     Securities giving rise to such indemnification obligation.

          (c) Conduct of Indemnification Proceedings. If any Proceeding shall be
     brought or asserted against any Person entitled to indemnity  hereunder (an
     "Indemnified  Party"),  such  Indemnified  Party shall promptly  notify the
     Person from whom indemnity is sought (the "Indemnifying Party") in writing,
     and the  Indemnifying  Party  shall  have the right to assume  the  defense
     thereof, including the employment of counsel reasonably satisfactory to the
     Indemnified  Party and the  payment of all fees and  expenses  incurred  in
     connection  with  defense  thereof;  provided,  that  the  failure  of  any
     Indemnified  Party to give such notice  shall not relieve the  Indemnifying
     Party of its obligations or liabilities pursuant to this Agreement,  except
     (and only) to the extent that it shall be finally  determined by a court of
     competent  jurisdiction  (which  determination  is not subject to appeal or
     further  review) that such failure shall have  prejudiced the  Indemnifying
     Party.

          An Indemnified  Party shall have the right to employ separate  counsel
     in any such Proceeding and to participate in the defense  thereof,  but the
     fees  and  expenses  of  such  counsel  shall  be at the  expense  of  such

                                       8


     Indemnified Party or Parties unless:  (1) the Indemnifying Party has agreed
     in writing to pay such fees and expenses;  (2) the Indemnifying Party shall
     have failed promptly to assume the defense of such Proceeding and to employ
     counsel  reasonably  satisfactory  to such  Indemnified  Party  in any such
     Proceeding;  or (3) the named parties to any such Proceeding (including any
     impleaded parties) include both such Indemnified Party and the Indemnifying
     Party, and such Indemnified Party shall have been advised by counsel that a
     conflict  of  interest  is  likely  to exist if the  same  counsel  were to
     represent such Indemnified Party and the Indemnifying Party (in which case,
     if such Indemnified  Party notifies the Indemnifying  Party in writing that
     it elects to employ  separate  counsel at the  expense of the  Indemnifying
     Party,  the  Indemnifying  Party  shall not have the  right to  assume  the
     defense  thereof  and the  reasonable  fees and  expenses  of one  separate
     counsel  shall  be  at  the  expense  of  the  Indemnifying   Party).   The
     Indemnifying  Party  shall not be  liable  for any  settlement  of any such
     Proceeding effected without its written consent, which consent shall not be
     unreasonably  withheld.  No  Indemnifying  Party  shall,  without the prior
     written  consent of the  Indemnified  Party,  effect any  settlement of any
     pending  Proceeding in respect of which any  Indemnified  Party is a party,
     unless  such  settlement   includes  an   unconditional   release  of  such
     Indemnified  Party from all liability on claims that are the subject matter
     of such Proceeding.

          All reasonable fees and expenses of the Indemnified  Party  (including
     reasonable  fees and  expenses to the extent  incurred in  connection  with
     investigating  or  preparing  to defend  such  Proceeding  in a manner  not
     inconsistent with this Section) shall be paid to the Indemnified  Party, as
     incurred,  within  ten  Trading  Days  of  written  notice  thereof  to the
     Indemnifying  Party;  provided,  that the Indemnified  Party shall promptly
     reimburse the Indemnifying Party for that portion of such fees and expenses
     applicable to such actions for which such Indemnified Party is not entitled
     to indemnification hereunder,  determined based upon the relative faults of
     the parties.

          (d) Contribution. If a claim for indemnification under Section 5(a) or
     5(b) is unavailable to an Indemnified  Party (by reason of public policy or
     otherwise),  then each  Indemnifying  Party, in lieu of  indemnifying  such
     Indemnified  Party,  shall contribute to the amount paid or payable by such
     Indemnified  Party as a result of such  Losses,  in such  proportion  as is
     appropriate  to reflect the relative  fault of the  Indemnifying  Party and
     Indemnified  Party in connection with the actions,  statements or omissions
     that  resulted  in such  Losses  as well as any  other  relevant  equitable
     considerations.   The  relative  fault  of  such  Indemnifying   Party  and
     Indemnified  Party shall be determined by reference to, among other things,
     whether  any action in  question,  including  any untrue or alleged  untrue
     statement of a material fact or omission or alleged  omission of a material
     fact,  has been taken or made by, or relates to  information  supplied  by,
     such  Indemnifying  Party or Indemnified  Party, and the parties'  relative
     intent,  knowledge,  access to  information  and  opportunity to correct or
     prevent such action, statement or omission. The amount paid or payable by a
     party as a result of any Losses shall be deemed to include,  subject to the
     limitations  set forth in Section 5(c), any reasonable  attorneys' or other
     reasonable  fees or expenses  incurred by such party in connection with any
     Proceeding  to the extent such party would have been  indemnified  for such
     fees or expenses if the  indemnification  provided  for in this Section was
     available to such party in accordance with its terms.

                                       9


          The parties  hereto  agree that it would not be just and  equitable if
     contribution  pursuant to this  Section  5(d) were  determined  by pro rata
     allocation  or by any other  method of  allocation  that does not take into
     account  the  equitable  considerations  referred  to  in  the  immediately
     preceding  paragraph.  Notwithstanding the provisions of this Section 5(d),
     no Holder shall be required to contribute,  in the aggregate, any amount in
     excess of the amount by which the proceeds actually received by such Holder
     from the  sale of the  Registrable  Securities  subject  to the  Proceeding
     exceeds  the amount of any  damages  that such  Holder has  otherwise  been
     required to pay by reason of such  untrue or alleged  untrue  statement  or
     omission or alleged omission, except in the case of fraud by such Holder.

          The indemnity and  contribution  agreements  contained in this Section
     are in addition to any liability that the Indemnifying  Parties may have to
     the Indemnified Parties.

     6. Miscellaneous

          (a) Remedies.  In the event of a breach by the Company or by a Holder,
     of any of their  obligations  under  this  Agreement,  each  Holder  or the
     Company,  as the case may be, in addition to being entitled to exercise all
     rights  granted  by law and under this  Agreement,  including  recovery  of
     damages,  will be entitled to specific performance of its rights under this
     Agreement.  The Company and each Holder agree that  monetary  damages would
     not provide  adequate  compensation  for any losses incurred by reason of a
     breach by it of any of the  provisions of this Agreement and hereby further
     agrees that, in the event of any action for specific performance in respect
     of such  breach,  it shall waive the defense  that a remedy at law would be
     adequate.

          (b)  No  Piggyback  on  Registrations.  Except  as  set  forth  on the
     Disclosure  Schedule,  neither the Company nor any of its security  holders
     (other  than the  Holders in such  capacity  pursuant  hereto)  may include
     securities  of the  Company  in a  Registration  Statement  other  than the
     Registrable  Securities,  and the  Company  shall not after the date hereof
     enter into any  agreement  providing  any such right to any of its security
     holders. Until the earlier of the Effective Date and September 6, 2003, the
     Company  shall not file any other  registration  statement  until after the
     Effective  Date without the consent of the Holders  holding at least 50% of
     the then  outstanding  Registrable  Securities,  which consent shall not be
     unreasonably withheld.

          (c) Compliance.  Each Holder  covenants and agrees that it will comply
     with  the  prospectus  delivery  requirements  of  the  Securities  Act  as
     applicable  to  it in  connection  with  sales  of  Registrable  Securities
     pursuant to a Registration Statement.

          (d) Discontinued Disposition. Each Holder agrees by its acquisition of
     such Registrable Securities that, upon receipt of a notice from the Company
     of the occurrence of any event of the kind described in Section 3(c),  such
     Holder  will  forthwith   discontinue   disposition  of  such   Registrable
     Securities  under a Registration  Statement until such Holder's  receipt of
     the  copies of the  supplemented  Prospectus  and/or  amended  Registration
     Statement or until it is advised in writing  (the  "Advice") by the Company

                                       10


     that the use of the applicable  Prospectus  may be resumed,  and, in either
     case, has received  copies of any additional or  supplemental  filings that
     are  incorporated  or  deemed  to be  incorporated  by  reference  in  such
     Prospectus or Registration  Statement.  The Company may provide appropriate
     stop orders to enforce the provisions of this paragraph.

          (e) Piggy-Back Registrations.  If at any time during the Effectiveness
     Period there is not an effective Registration Statement covering all of the
     Registrable  Securities and the Company shall determine to prepare and file
     with the  Commission a registration  statement  relating to an offering for
     its own account or the account of others under the Securities Act of any of
     its  equity  securities,  other  than on  Form  S-4 or Form  S-8  (each  as
     promulgated under the Securities Act) or their then equivalents relating to
     equity securities to be issued solely in connection with any acquisition of
     any entity or business or equity securities issuable in connection with the
     stock option or other employee  benefit plans,  then the Company shall send
     to each  Holder a  written  notice  of such  determination  and,  if within
     fifteen  days  after  the date of such  notice,  any such  Holder  shall so
     request  in  writing,  the  Company  shall  include  in  such  registration
     statement  all or any  part  of such  Registrable  Securities  such  Holder
     requests  to be  registered,  subject  to  customary  underwriter  cutbacks
     applicable to all holders of registration rights.

          (f)  Amendments  and  Waivers.   The  provisions  of  this  Agreement,
     including the provisions of this sentence, may not be amended,  modified or
     supplemented,  and waivers or consents to  departures  from the  provisions
     hereof may not be given,  unless the same shall be in writing and signed by
     the  Company  and  Holders  holding  at least  66% of the then  outstanding
     Registrable Securities.

          (g) Notices. Any and all notices or other communications or deliveries
     required  or  permitted  to be provided  hereunder  shall be in writing and
     shall be deemed  given and  effective  on the  earliest  of (i) the date of
     transmission, if such notice or communication is delivered via facsimile at
     the facsimile  number  provided for below prior to 6:30 p.m. (New York City
     time)  on  a  Trading  Day,   (ii)  the  Trading  Day  after  the  date  of
     transmission, if such notice or communication is delivered via facsimile at
     the facsimile number provided for below later than 6:30 p.m. (New York City
     time) on any date and earlier than 11:59 p.m.  (New York City time) on such
     date,  (iii) the Trading  Day  following  the date of  mailing,  if sent by
     nationally  recognized  overnight  courier  service,  or (iv)  upon  actual
     receipt  by the party to whom  such  notice is  required  to be given.  The
     address  for  such  notices  and  communications  shall  be  delivered  and
     addressed as set forth in the Purchase Agreement

          (h) Successors and Assigns.  This Agreement shall inure to the benefit
     of and be binding upon the successors and permitted  assigns of each of the
     parties  and  shall  inure to the  benefit  of each  Holder.  Except to its
     successors,  the Company may not assign its rights or obligations hereunder
     without the prior  written  consent of each Holder.  Each Holder may assign
     their  respective  rights  hereunder  in the manner  and to the  Persons as
     permitted under the Purchase Agreement.

                                       11



          (i) Execution and Counterparts.  This Agreement may be executed in any
     number of  counterparts,  each of which when so executed shall be deemed to
     be an original and, all of which taken  together  shall  constitute one and
     the same  Agreement.  In the  event  that any  signature  is  delivered  by
     facsimile  transmission,  such  signature  shall  create  a  valid  binding
     obligation  of the party  executing  (or on whose behalf such  signature is
     executed)  the same  with the same  force and  effect as if such  facsimile
     signature were the original thereof.

          (j)  Governing  Law.  All  questions   concerning  the   construction,
     validity,  enforcement  and  interpretation  of  this  Agreement  shall  be
     governed by and construed and enforced in accordance with the internal laws
     of the State of New York,  without regard to the principles of conflicts of
     law thereof.  Each party agrees that all legal  proceedings  concerning the
     interpretations,  enforcement and defense of the transactions  contemplated
     by this Agreement (whether brought against a party hereto or its respective
     affiliates,  directors, officers, shareholders,  employees or agents) shall
     be commenced  exclusively  in the state and federal  courts  sitting in the
     City of New York, New York. Each party hereto hereby irrevocably submits to
     the exclusive  jurisdiction  of the state and federal courts sitting in the
     City of New York, New York for the adjudication of any dispute hereunder or
     in  connection  herewith  or with any  transaction  contemplated  hereby or
     discussed  herein  (including with respect to the enforcement of the any of
     this Agreement), and hereby irrevocably waives, and agrees not to assert in
     any suit, action or proceeding, any claim that it is not personally subject
     to the jurisdiction of any such court, that such suit, action or proceeding
     is improper.  Each party hereto hereby  irrevocably waives personal service
     of process and consents to process being served in any such suit, action or
     proceeding by mailing a copy thereof via  registered  or certified  mail or
     overnight delivery (with evidence of delivery) to such party at the address
     in effect  for  notices  to it under this  Agreement  and agrees  that such
     service shall constitute good and sufficient  service of process and notice
     thereof.  Nothing  contained herein shall be deemed to limit in any way any
     right to serve  process in any manner  permitted by law.  Each party hereto
     hereby  irrevocably  waives,  to the fullest extent permitted by applicable
     law, any and all right to trial by jury in any legal proceeding arising out
     of or relating to this Agreement or the transactions  contemplated  hereby.
     If either  party  shall  commence  an action or  proceeding  to enforce any
     provisions of this Agreement,  then the prevailing  party in such action or
     proceeding  shall be reimbursed  by the other party for its attorneys  fees
     and other costs and expenses incurred with the  investigation,  preparation
     and prosecution of such action or proceeding.

          (k) Cumulative  Remedies.  The remedies provided herein are cumulative
     and not exclusive of any remedies provided by law.

          (l) Severability.  If any term, provision,  covenant or restriction of
     this Agreement is held by a court of competent  jurisdiction to be invalid,
     illegal,  void or  unenforceable,  the remainder of the terms,  provisions,
     covenants and  restrictions set forth herein shall remain in full force and
     effect and shall in no way be affected,  impaired or  invalidated,  and the
     parties hereto shall use their commercially  reasonable efforts to find and
     employ an alternative  means to achieve the same or substantially  the same
     result  as  that  contemplated  by  such  term,   provision,   covenant  or
     restriction.  It is hereby  stipulated  and declared to be the intention of

                                       12


     the parties that they would have executed the remaining terms,  provisions,
     covenants  and  restrictions  without  including  any of such  that  may be
     hereafter declared invalid, illegal, void or unenforceable.

          (m) Headings.  The headings in this  Agreement are for  convenience of
     reference only and shall not limit or otherwise affect the meaning hereof.

          (n)  Independent  Nature of Purchasers'  Obligations  and Rights.  The
     obligations of each  Purchaser  hereunder is several and not joint with the
     obligations of any other  Purchaser  hereunder,  and no Purchaser  shall be
     responsible in any way for the  performance of the obligations of any other
     Purchaser hereunder.  Nothing contained herein or in any other agreement or
     document  delivered  at any closing,  and no action taken by any  Purchaser
     pursuant hereto or thereto, shall be deemed to constitute the Purchasers as
     a partnership, an association, a joint venture or any other kind of entity,
     or  create a  presumption  that the  Purchasers  are in any way  acting  in
     concert with respect to such obligations or the  transactions  contemplated
     by this Agreement.  Each Purchaser shall be entitled to protect and enforce
     its rights,  including  without  limitation  the rights arising out of this
     Agreement,  and it shall not be  necessary  for any other  Purchaser  to be
     joined as an additional party in any proceeding for such purpose.

                            *************************

                                       13



                  IN  WITNESS   WHEREOF,   the  parties   have   executed   this
Registration Rights Agreement as of the date first written above.

                               CYTOGEN CORPORATION


                               By: /s/ Michael D. Becker
                                   ----------------------------------

                                   Name:  Michael D. Becker
                                   Title: President and Chief Executive Officer

                     [PURCHASERS' SIGNATURE PAGES TO FOLLOW]


                                       14



                       [PURCHASER'S SIGNATURE PAGE TO RRA]


                            BONANZA MASTER FUND LTD.

                            By: /s/ Brian Ladin
                                ------------------------------------
                                 Name:  Brian Ladin
                                 Title: Managing Director

                     [PURCHASERS' SIGNATURE PAGES TO FOLLOW]


                                       15




                       [PURCHASER'S SIGNATURE PAGE TO RRA]

BAYSTAR CAPITAL II LP


By: /s/ Steve Derby
    -------------------------------------
       Name:  Steve Derby
       Title: Managing Member



                                       16

                                                                         ANNEX A

                              Plan of Distribution

         The  Selling  Stockholders  and any of their  pledgees,  assignees  and
successors-in-interest  may, from time to time,  sell any or all of their shares
of Common Stock on any stock exchange,  market or trading  facility on which the
shares  are traded or in private  transactions.  These  sales may be at fixed or
negotiated  prices.  The  Selling  Stockholders  may  use any one or more of the
following methods when selling shares:

     -    ordinary   brokerage   transactions  and  transactions  in  which  the
          broker-dealer solicits purchasers;

     -    block  trades  in which the  broker-dealer  will  attempt  to sell the
          shares as agent but may  position and resell a portion of the block as
          principal to facilitate the transaction;

     -    purchases  by  a   broker-dealer   as  principal  and  resale  by  the
          broker-dealer for its account;

     -    an  exchange   distribution  in  accordance  with  the  rules  of  the
          applicable exchange;

     -    privately negotiated transactions;

     -    settlement of short sales;

     -    broker-dealers  may  agree  with the  Selling  Stockholders  to sell a
          specified number of such shares at a stipulated price per share;

     -    a combination of any such methods of sale; and

     -    any other method permitted pursuant to applicable law.

         The Selling  Stockholders may also sell shares under Rule 144 under the
Securities Act, if available, rather than under this prospectus.

         Broker-dealers  engaged by the  Selling  Stockholders  may  arrange for
other  brokers-dealers  to  participate  in sales.  Broker-dealers  may  receive
commissions or discounts from the Selling Stockholders (or, if any broker-dealer
acts as agent for the purchaser of shares,  from the purchaser) in amounts to be
negotiated.  The  Selling  Stockholders  do not  expect  these  commissions  and
discounts to exceed what is customary in the types of transactions involved.

         The  Selling  Stockholders  may  from  time to time  pledge  or grant a
security  interest  in some or all of the shares of common  stock  owned by them
and,  if they  default in the  performance  of their  secured  obligations,  the
pledgees or secured  parties may offer and sell the shares of common  stock from
time to time under this  prospectus,  or under an amendment  to this  prospectus
under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933

                                       17


amending the list of Selling Stockholders to include the pledgee,  transferee or
other successors in interest as Selling Stockholders under this prospectus.

         The  Selling  Stockholders  and any  broker-dealers  or agents that are
involved  in selling  the shares may be deemed to be  "underwriters"  within the
meaning of the Securities Act in connection with such sales. In such event,  any
commissions  received  by such  broker-dealers  or agents  and any profit on the
resale  of the  shares  purchased  by  them  may be  deemed  to be  underwriting
commissions or discounts under the Securities Act. The Selling Stockholders have
informed  the  Company  that it does not have any  agreement  or  understanding,
directly or indirectly, with any person to distribute the Common Stock.

         The Company is required  to pay all fees and  expenses  incident to the
registration  of the shares.  The Company  has agreed to  indemnify  the Selling
Stockholders against certain losses, claims, damages and liabilities,  including
liabilities under the Securities Act.



                                       18