MARK S. DODSON             Exhibit 5(a)
                                   Attorney at law
                                220 N.W. Second Avenue
                               Portland, Oregon  97209




                                             March 19, 1998




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

          Dear Sirs:

                    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, contemplating the issuance and sale from time
          to time by the Company of up to 2,500,000 additional shares of
          its Common Stock (New Stock) and the Common Share Purchase Rights
          appurtenant thereto (Rights), 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 action necessary to make the New Stock legally
          issued, fully paid and non-assessable and the Rights appurtenant
          to the New Stock legally issued will have been taken when:

                    (a)  the Registration Statement shall have become
                    effective;

                    (b)  the Company's Board of Directors or a duly
                    authorized committee thereof shall have taken
                    appropriate action with respect to the issuance and
                    sale of the New Stock;

                    (c)  the issuance of the New 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;

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

                    (e)  the Rights appurtenant to the New 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 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.