EXHIBIT 5.1

July 19, 1999

Cytogen Corporation
600 College Road East
Princeton, New Jersey 08540

Ladies and Gentlemen:

The undersigned has acted as counsel to Cytogen Corporation, a Delaware
corporation (the "Company"), in connection with the preparation and filing by
the Company of a Registration Statement on Form S-3 (the "Registration
Statement") under the Securities Act of 1933, as amended (the "Act"), for the
registration of up to $5 million in shares of common stock, $.01 par value per
share (the "Common Stock"), of the Company.

I have examined and am familiar with originals or copies, certified or otherwise
identified to our satisfaction, of such documents, corporate records,
certificates of public officials and officers of the Company and such other
instruments as I have deemed necessary or appropriate as a basis for the
opinions expressed below, including the Registration Statement, the Restated
Certificate of Incorporation of the Company and the By-laws of the Company.

Based on the foregoing, I am of the opinion that the Common Stock issuable
under the Registration Statement has been duly authorized and reserved for
issuance and, when duly issued and delivered, will be validly issued, fully paid
and nonassessable.

I hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement.  In giving such consent, I do not thereby admit
that we come within the category of persons whose consent is required under
Section 7 of the Act or the rules and regulations of the Securities and Exchange
Commission thereunder.

I express no opinion as to the laws of any jurisdiction other than the
general corporate laws of the State of Delaware and the federal law of the
United States of America. The foregoing opinion is rendered as of the date
hereof, and I assume no obligation to update such opinion to reflect any facts
or circumstances which may hereafter come to my attention or any changes in the
law which may hereafter occur.

                                       Very truly yours,



                                       /s/ Donald F. Crane
                                      -------------------------
                                      Donald F. Crane, Jr.