EXHIBIT 5.1


                                 MARK S. DODSON
                                Attorney at Law
                              220 NW Second Avenue
                          Portland, Oregon 97209-3991


                                        September 22, 2000


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

Ladies and Gentlemen:

          Referring to the Registration Statement on Form S-8 ("Registration
Statement") to be filed by Northwest Natural Gas Company ("Company") on or about
the date hereof with the Securities and Exchange Commission ("Commission") under
the Securities Act of 1933, as amended, for the registration of up to 200,000
shares of the Company's common stock, $31/6 par value ("Stock"), and the rights
to purchase common stock appurtenant thereto ("Rights"), to be offered from time
to time in connection with the Northwest Natural Gas Company Employee Stock
Purchase Plan ("Plan"), I am of the opinion that:

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

          2.   All requisite action necessary to make the Stock validly
issued, fully paid and non-assessable and the Rights validly issued will have
been taken when:

          (a) the Stock shall have been issued and delivered for the
consideration contemplated in the Plan; and

          (b) the Rights 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 Shareholders 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 and had such consultations with the Company's State
of Washington counsel as I believe necessary to satisfy myself as to questions
of Washington law. As to all matters of New York law, I have relied upon an
opinion of even date herewith addressed to you by Thelen Reid & Priest LLP which
is filed as Exhibit 5.2 to the Registration Statement.

          I hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement.

                                        Very truly yours,

                                        /s/  Mark S. Dodson, Esq.

                                        Mark S. Dodson, Esq.