Exhibit 5.1


                                        December 18, 2003


Nastech Pharmaceutical Company Inc.
3450 Monte Villa Parkway
Bothell, Washington  98021

     Re:        Registration Statement on Form S-3

Ladies and Gentlemen:

     We have acted as counsel to Nastech Pharmaceutical Company Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing of a
Registration Statement on Form S-3 (the "Registration Statement"), for the
purpose of registering (i) shares (the "Shares") of the common stock, par value
$0.006 per share, of the Company (the "Common Stock"); and (ii) warrants (the
"Warrants") to purchase shares of Common Stock.

     We have made such inquiries and reviewed such documents and records as we
have deemed necessary to enable us to express an opinion on the matters covered
hereby, and we have also examined and relied upon representations, statements or
certificates of public officials and officers and representatives of the
Company.

     Based upon and subject to the foregoing, we are of the opinion that:

1. With respect to the Shares, when (a) the Board of Directors of the Company or
   an authorized committee thereof has taken all necessary corporate action to
   authorize the issuance and sale of the Shares; and (b) certificates
   evidencing such Shares have been duly executed by a duly authorized officer
   of the Company, countersigned (if applicable) by an authorized officer of the
   transfer agent and registrar for the Common Stock, registered by such
   transfer agent and registrar, and issued and delivered against payment of the
   consideration therefor as determined by appropriate corporate action of the
   Company (assuming that the consideration so received has a value not less
   than the par value of such Shares and that a sufficient number of shares of
   Common Stock are authorized and available for issuance), all in accordance
   with such corporate action, the issuance and sale of the Shares will have
   been duly authorized, and such Shares will be validly issued, fully paid and
   nonassessable.

2. With respect to the Warrants and the shares of Common Stock (the "Warrant
   Shares") issued upon exercise thereof, when (a) the Board of Directors of the
   Company or an authorized committee thereof has taken all necessary corporate
   action to authorize the issuance and sale of the Warrants and the Warrant
   Shares, and to authorize and approve the form, terms, execution and delivery
   of certificates evidencing such Warrants and a related agreement (the
   "Warrant Agreement"), if any; (b) the Warrant Agreement, if any, has been
   duly executed and delivered by a duly authorized officer of the Company and
   the warrant agent thereunder, if any; (c) certificates evidencing such
   Warrants (in such form and with such terms) have been duly executed and
   attested by a duly authorized officer of the Company, authenticated by such
   warrant agent, if any, and issued and delivered against payment of the
   consideration therefor as determined by appropriate corporate action of the
   Company; and (d) appropriate corporate action has been taken by the Company
   to reserve the Warrant Shares for issuance upon exercise of such Warrants
   upon payment of the exercise price therefor as determined by appropriate
   corporate action (assuming that the consideration so received has a value not
   less than the par value of such Warrant Shares and that a sufficient number
   of shares of Common Stock are authorized and available for issuance), all in
   accordance with any applicable Warrant Agreement and such corporate action,
   the issuance and sale of the Warrants and upon exercise thereof, the Warrant
   Shares, will have been duly authorized, and such Warrants and Warrant Shares
   will be validly issued, fully paid and nonassessable.

     We do not express any opinion with respect to any law other than the laws
of the State of New York, the Delaware General Corporation Law and the federal
laws of the United States of America.  This opinion is rendered only with
respect to the laws and legal interpretations and the facts and circumstances in
effect on the date hereof which are in effect.

     We hereby consent to the use of this opinion as Exhibit 5.1 to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the prospectus included in the Registration Statement.  In giving
this consent, we do not thereby admit that we are within the category of persons
whose consent is required under Section 7 of the Securities Act of 1933, as
amended, or the rules and regulations promulgated thereunder.

                                   Very truly yours,



                                   /s/ Kramer Levin Naftalis & Frankel LLP