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                                                                    EXHIBIT 5.1


                        (COOLEY GODWARD LLP LETTERHEAD)



September 29, 1997



Coulter Pharmaceutical, Inc.
550 California Avenue, Suite 200
Palo Alto, California 94306-1440

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by Coulter Pharmaceutical, Inc. (the "Company") of a
Registration Statement on Form S-1 on September 29, 1997, as amended, (the
"Registration Statement") with the Securities and Exchange Commission covering
the offering of up to Two Million Three Hundred Thousand (2,300,000) shares of
the Company's Common Stock, $.001 par value (the "Shares").

In connection with this opinion, we have examined the Registration Statement
and related Prospectus, your Restated Certificate of Incorporation and Bylaws,
as amended, and such other documents, records, certificates, memoranda and
other instruments as we deem necessary as a basis for this opinion. We have
assumed the genuineness and authenticity of all documents submitted to us as
originals, the conformity to originals of all documents submitted to us as
copies thereof, and the due execution and delivery of all documents where due
execution and delivery are a prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the Shares, when sold and issued in accordance with the Registration
Statement and related prospectus, will be validly issued, fully paid, and
nonassessable.

We consent to the filing of this opinion as an exhibit to the Registration
Statement.

Very truly yours,

COOLEY GODWARD LLP


/s/ James C. Kitch
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James C. Kitch