Exhibit 5(b)


                                             July 5, 2001


Avista Corporation
1411 East Mission Avenue
Spokane, WA 99202

Ladies and Gentlemen:

          We are acting as counsel to Avista Corporation, a Washington
corporation (the "Company"), in connection with the 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"), relating to the registration of
3,700,000 shares of the Company's Common Stock, no par value (the "New Shares"),
as described in the Registration Statement. The New Shares will be offered and
issued together with the related preferred share purchase rights (the "New
Rights") in accordance with the Rights Agreement, dated as of November 15, 1999
(the "Rights Agreement"), between the Company and The Bank of New York, as
rights agent.

          Subject to the qualifications hereinafter expressed, we are of the
opinion that, when the New Shares are issued and delivered as contemplated in
the Registration Statement, the New Shares will be legally issued, fully paid
and non-assessable and the New Rights will be legally issued.

          It is also our opinion that Section 23B.06.240 of the Washington
Business Corporation Act permits Washington corporations to enter into
shareholder rights plans, such as the Rights Agreement, and to issue rights
thereunder, such as the New Rights. However, we are not aware of any court
decisions applying Washington law that address the validity of actions taken by
the board of directors of a Washington corporation in authorizing a shareholder
rights plan or the issuance of rights thereunder.

          In our view, it is reasonable to assume, and we do assume, that a
court applying the law of the Sate of Washington, when presented with questions
concerning matters such as the authorization and issuance of the New Rights,
after giving effect to the "business judgment rule" under Washington statutory
and case law, most likely would look to and apply the corporation law of the
State of Delaware. Accordingly, our opinion relating to the legal issuance of
the New Rights is based, in part, upon such assumption.

          We do not herein express any opinion as to the enforceability of the
New Rights or the Rights Agreement.





          For purposes of the opinions set forth above, we have assumed that the
New Shares and the New Rights will be issued and sold in compliance with the due
authorization of the Company's Board of Directors and the "Orders" referred to
in the aforesaid opinion of Heller Ehrman White & McAuliffe LLP.

          To the extent that the opinions set forth above relate to or are
dependent upon matters governed by the laws of the States of Washington,
California, Idaho, Montana and Oregon, we have relied the opinion of Heller
Ehrman White & McAuliffe LLP, which is being filed as Exhibit 5(a) to the
Registration Statement, and our opinions are subject to the limitations and
qualifications set forth in such opinion of Heller Ehrman White & McAuliffe LLP.

          We hereby consent to the filing of this opinion as Exhibit 5(b) to the
Registration Statement and to the references to our firm, as counsel, in the
Registration Statement and in the prospectus contained therein. In giving the
foregoing consent, we do not admit that we are within the category of persons
whose consent is required under Section 7 of the Act or the rules and
regulations promulgated thereunder.

                                             Very truly yours,

                                             /s/ THELEN REID & PRIEST LLP

                                             THELEN REID & PRIEST LLP


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