Exhibit 5(b)


                            THELEN REID & PRIEST LLP
NEW YORK                        ATTORNEYS AT LAW
SAN FRANCISCO                 40 WEST 57TH STREET
WASHINGTON, D.C.            NEW YORK, N.Y. 10019-4097
LOS ANGELES           TEL (212) 603-2000 FAX (212) 603-2001
SILICON VALLEY                 www.thelenreid.com
MORRISTOWN, N.J.


                                 October 4, 2002


Northwest Natural Gas Company
220 N.W. Second Avenue
Portland, Oregon  97209

Ladies and Gentlemen:

     With respect to the Registration Statement on Form S-3 to be filed with the
Securities and Exchange Commission (the "Commission") on or about the date
hereof by Northwest Natural Gas Company (the "Company") for the registration
under the Securities Act of 1933, as amended ("Securities Act"), of $150,000,000
aggregate principal amount of Secured Medium-Term Notes, Series B ("Secured
Notes") and Unsecured Medium-Term Notes, Series B ("Unsecured Notes") (the
Secured Notes and the Unsecured Notes are hereinafter collectively referred to
as the "Notes") to be issued by the Company, and for the qualification under the
Trust Indenture Act of 1939, as amended ("Trust Indenture Act"), of the
Company's Mortgage and Deed of Trust, as supplemented ("Mortgage"), under which
the Secured Notes are to be issued, and the Company's Indenture ("Indenture")
under which the Unsecured Notes are to be issued, we are of the opinion that:

     1.   The Company is a corporation duly organized and validly existing under
the laws of the State of Oregon.

     2.   All action necessary to make the Notes legally issued and valid and
binding obligations of the Company will have been taken when:

          (a) the Company's Registration Statement on Form S-3, as it may be
amended, shall have become effective in accordance with the applicable
provisions of the Securities Act, and a supplement or supplements to the
Prospectus constituting a part of the Registration Statement specifying certain
details with respect to the offering or offerings of the Notes shall have been
filed with the Commission, and the Mortgage and the Indenture shall have been
qualified under the Trust Indenture Act;

          (b) an appropriate order or orders shall have been issued by the
Washington Utilities and Transportation Commission authorizing the issuance and
sale by the Company of the Notes; and

          (c) the Notes shall have been appropriately issued and delivered for
the consideration contemplated by, and otherwise in conformity with, the acts,
proceedings and documents referred to above, the authorizing resolutions of the





Board of Directors of the Company relating to the Notes and the order of the
Public Utility Commission of Oregon authorizing the issuance and sale by the
Company of the Notes.

     We are members of the New York Bar and do not hold ourselves out as experts
on the laws of any other state. As to all matters of Oregon and Washington law,
we have relied upon an opinion of even date herewith addressed to you by Mark S.
Dodson, Esq., which is filed as Exhibit 5(a) to the Registration Statement.

     We hereby consent to the use of this opinion as an exhibit to the
Registration Statement, as it may be amended, and consent to such references to
our firm as may be made in such Registration Statement and in the Prospectus. In
giving the foregoing consent, we do not thereby admit that we belong to the
category of persons whose consent is required under Section 7 of the Securities
Act, or the rules and regulations promulgated by the Commission thereunder.

                                          Very truly yours,

                                          /s/ Thelen Reid & Priest LLP

                                          THELEN REID & PRIEST LLP