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                                                                     EXHIBIT 5.1



                                October 10, 2001



NeoRx Corporation
410 West Harrison Street
Seattle, Washington 98119

         RE:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

         We have acted as counsel to you in connection with the preparation of a
Registration Statement on Form S-8 (the "Registration Statement") under the
Securities Act of 1933, as amended ("the Act"), which you are filing with the
Securities and Exchange Commission with respect to up to 1,300,000 shares of
common stock, $0.02 par value per share, which may be issued under the NeoRx
Corporation Restated 1994 Stock Option Plan (the "Plan") and up to 150,000
shares of common stock, par value $0.02 per share, which may be issued under the
Stock Option Agreement with Douglass B. Given, M.D. (the "Given Agreement"). The
aggregate 1,450,000 shares of common stock that may be issued under the Plan and
the Given Agreement pursuant to the Registration Statement are hereinafter
referred to as the "Shares".

         We have examined the Registration Statement and such documents and
records of NeoRx Corporation as we have deemed necessary for the purpose of this
opinion. In giving this opinion, we are assuming the authenticity of all
instruments presented to us as originals, the conformity with originals of all
instruments presented to us as copies and the genuineness of all signatures.

         Based upon and subject to the foregoing, we are of the opinion that any
original issuance Shares that may be issued pursuant to the Plan and the Given
Agreement have been duly authorized and that, upon the due execution by NeoRx
Corporation of any certificates representing the Shares, the registration by its
registrar of such Shares and the sale thereof by NeoRx Corporation in accordance
with the terms of the Plan and the Given Agreement, and the receipt of
consideration therefor in accordance with the terms of the Plan and the Given
Agreement, such Shares will be validly issued, fully paid and nonassessable.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In giving such consent, we do not admit that we are in
the category of persons whose consent is required under Section 7 of the Act.

                                                     Very truly yours,

                                                     /s/ Perkins Coie LLP