Exhibit 5(a)


                         [LETTERHEAD OF MARK S. DODSON]



                                             August 22, 2001



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

Ladies and Gentlemen:

          With reference to the Registration Statement to be filed by the
Company on or about the date hereof with the Securities and Exchange Commission
under the Securities Act of 1933, as amended (the "Act"), contemplating the sale
by the Company of 750,000 additional shares of its Common Stock ("Stock") and
the Common Share Purchase Rights appurtenant thereto ("Rights") pursuant to its
Dividend Reinvestment and Stock Purchase Plan (the "Plan"), I am of the opinion
that:

     1.   The Company has been duly incorporated and is validly existing
under the laws of the State of Oregon and is qualified to do business in the
State of Washington.

     2.   All of the presently issued and outstanding shares of Stock have
been legally issued and are fully paid and non-assessable.

     3.   All of the presently issued and outstanding Rights have been
legally issued.

     4.   To the extent that the Company shall issue authorized but unissued
shares of Stock and Rights appurtenant thereto for sale pursuant to the Plan,
all action necessary to make such Stock legally issued, fully paid and
non-assessable and the Rights appurtenant to such Stock legally issued will have
been taken when:

     (a) the issuance of such Stock shall have been authorized by the Oregon
     Public Utility Commission and the Washington Utilities and Transportation
     Commission shall have issued an order establishing compliance with
     applicable statutory provisions with respect to such issuance;




Mark S. Dodson
August 22, 2001
Page 2


     (b) such Stock shall have been issued and delivered for the consideration
     contemplated in the Registration Statement; and

     (c) the Rights appurtenant to such Stock shall have been issued in
     accordance with the terms of the Rights Agreement dated as of February 27,
     1996 between the Company and Boatmen's Trust Company (ChaseMellon
     Shareholder Services, successor).

          I am a member of the bar of the State of Oregon, but not of the State
of Washington. In rendering this opinion, I have made such reviews of the laws
of the State of Washington as I believe necessary to satisfy myself as to
questions of Washington law.

          I consent to the use of this opinion as an exhibit to the Registration
Statement and to the use of my name, as counsel, therein.

                                             Very truly yours,

                                             /s/ Mark S. Dodson
                                             Mark S. Dodson, Esq.


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