S-8

As filed with the Securities and Exchange Commission on June 13, 2006

Registration No. 333-            

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-8

REGISTRATION STATEMENT

Under

THE SECURITIES ACT OF 1933

NORTHWEST NATURAL GAS COMPANY

(Exact name of registrant as specified in its charter)

OREGON	93-0256722
(State or other jurisdiction of incorporation or organization)	(IRS Employer Identification No.)
220 N.W. Second Avenue Portland, Oregon	97209
(Address of Principal Executive Offices)	(Zip Code)

NORTHWEST NATURAL GAS COMPANY

EMPLOYEE STOCK PURCHASE PLAN

(Full title of plan)

C. J. RUE

Secretary

Northwest Natural Gas Company

220 N.W. Second Avenue

Portland, Oregon 97209

(Name and address of agent for service)

Telephone number, including area code, of agent for service: (503) 226-4211

Copy to:

STUART CHESTLER

Stoel Rives LLP

900 SW Fifth Avenue, Suite 2600

Portland, Oregon 97204-1268

CALCULATION OF REGISTRATION FEE

Title of Securities to be Registered	Amount to Be Registered	Proposed Maximum Offering Price Per Share(1)		Proposed Maximum Aggregate Offering Price(1)		Amount of Registration Fee
Common Stock	200,000 shares	$	34.73	$	6,946,000	$	743.00

⁽¹⁾ The proposed maximum offering price per share and the proposed maximum aggregate offering price are estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act of 1933. The calculation of the registration fee for the shares to be registered is based on $34.73, which was the average of the high and low prices of a share of the Common Stock on June 6, 2006 on the New York Stock Exchange.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents By Reference.

The following documents filed by Northwest Natural Gas Company (the “Company”) with the Securities and Exchange Commission are incorporated herein by reference:

(a) The Company’s latest annual report filed pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 or the latest prospectus filed pursuant to Rule 424(b) under the Securities Act of 1933 that contains audited financial statements for the Company’s latest fiscal year for which such statements have been filed.

(b) All other reports filed pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 since the end of the fiscal year covered by the Company’s annual report or prospectus referred to in (a) above.

(c) The description of the Common Stock of the Company contained in the Company’s registration statement filed under Section 12 of the Securities Exchange Act of 1934, including any amendments or reports filed for the purpose of updating the description.

All reports and other documents subsequently filed by the Company pursuant to Sections 13(a) and (c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended, prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities remaining unsold, shall be deemed to be incorporated by reference herein and to be a part hereof from the date of the filing of such reports and documents.

Item 4. Description of Securities.

Not Applicable.

Item 5. Interests of Named Experts and Counsel.

Not Applicable.

Item 6. Indemnification of Directors and Officers.

The Oregon Business Corporation Act (the “Act”) provides, in general, that a director or officer of a corporation who has been or is threatened to be made a defendant in a legal proceeding because that person is or was a director or officer of the corporation:

(1) shall be indemnified by the corporation for all expenses of such litigation when the director or officer is wholly successful on the merits or otherwise;

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(2) may be indemnified by the corporation for the expenses, judgments, fines and amounts paid in settlement of such litigation (other than a derivative lawsuit) if he or she acted in good faith and in a manner reasonably believed to be in, or at least not opposed to, the best interests of the corporation (and, in the case of a criminal proceeding, had no reasonable cause to believe the conduct was unlawful); and

(3) may be indemnified by the corporation for expenses of a derivative lawsuit (a suit by a shareholder alleging a breach by a director or officer of a duty owed to the corporation) if he or she acted in good faith and in a manner reasonably believed to be in, or at least not opposed to, the best interests of the corporation, provided the director or officer is not adjudged liable to the corporation.

The Act also authorizes the advancement of litigation expenses to a director or officer upon receipt of a written affirmation of the director’s or officer’s good faith belief that the standard of conduct in Section (2) or (3) above has been met and a written undertaking by such director or officer to repay such expenses if it is ultimately determined that he or she did not meet that standard and, therefore, is not entitled to be indemnified. The Act also provides that the indemnification provided thereunder shall not be deemed exclusive of any other rights to which those indemnified may be entitled under any bylaw, agreement, vote of shareholders or disinterested directors or otherwise.

The Company’s Bylaws provide that the Company shall indemnify directors and officers to the fullest extent permitted under the Act, thus making mandatory the discretionary indemnification authorized by the Act.

The Company’s Restated Articles of Incorporation provide that the Company shall indemnify its officers and directors to the fullest extent permitted by law, which may be broader than the indemnification authorized by the Act.

The Company’s shareholders have approved and the Company has entered into indemnity agreements with its directors and officers which provide for indemnity to the fullest extent permitted by law and also alter or clarify the statutory indemnity in the following respects:

(1) prompt advancement of litigation expenses is provided if the director or officer makes the required affirmation and undertaking;

(2) the director or officer is permitted to enforce the indemnity obligation in court and the burden is on the Company to prove that the director or officer is not entitled to indemnification;

(3) indemnity is explicitly provided for judgments and settlements in derivative actions;

(4) prompt indemnification is provided unless a determination is made that the director or officer is not entitled to indemnification; and

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(5) partial indemnification is permitted if the director or officer is not entitled to full indemnification.

The Company maintains in effect a policy of insurance providing for reimbursement to the Company of payments made to directors and officers as indemnity for damages, judgments, settlements, costs and expenses incurred by them which the Company may be required or permitted to make according to applicable law, common or statutory, or under provisions of its Restated Articles of Incorporation, Bylaws or agreements effective under such laws.

Item 7. Exemption from Registration Claimed.

Not Applicable.

Item 8. Exhibits.

4.1 Restated Articles of Incorporation of the Company.

4.2 Bylaws of the Company, as amended. Incorporated by reference to Exhibit 3 to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2004, File No. 001-15973.

5.1 Opinion of Stoel Rives LLP.

23.1 Consent of PricewaterhouseCoopers LLP.

23.2 Consent of Stoel Rives LLP (included in Exhibit 5.1).

24.1 Power of Attorney (see page II-6).

Item 9. Undertakings.

(a) The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of the securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission

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pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities: The undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of

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the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

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POWER OF ATTORNEY

Each director and/or officer of the registrant whose signature appears hereinafter hereby appoints Mark S. Dodson, David H. Anderson and C.J. Rue, the Agents for Service named in this registration statement, and each of them severally, as his or her attorney-in-fact to sign in his or her name and behalf, in any and all capacities stated below, and to file with the Securities and Exchange Commission, any and all amendments, including post-effective amendments, to this registration statement, and the registrant hereby also appoints each such Agent for Service as its attorney-in-fact with like authority to sign and file any such amendments in its name and behalf.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Portland, State of Oregon, on June 13, 2006.

NORTHWEST NATURAL GAS COMPANY
By	/S/ MARK S. DODSON
	Mark S. Dodson
	President and Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/S/ MARK S. DODSON Mark S. Dodson	President and Chief Executive Officer and Director (Principal Executive Officer)	June 13, 2006
/S/ DAVID H. ANDERSON David H. Anderson	Senior Vice President and Chief Financial Officer (Principal Financial Officer)	June 13, 2006
/S/ STEPHEN P. FELTZ Stephen P. Feltz	Treasurer and Controller (Principal Accounting Officer)	June 13, 2006
/S/ TIMOTHY P. BOYLE Timothy P. Boyle	Director	June 1, 2006
Martha L. Byorum	Director

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/S/ JOHN D. CARTER John D. Carter	Director	June 1, 2006
/S/ C. SCOTT GIBSON C. Scott Gibson	Director	June 1, 2006
/S/ TOD R. HAMACHEK Tod R. Hamachek	Director	June 3, 2006
/S/ RANDALL C. PAPÉ Randall C. Papé	Director	June 5, 2006
/S/ RICHARD G. REITEN Richard G. Reiten	Director	June 2, 2006
/S/ KENNETH THRASHER Kenneth Thrasher	Director	June 1, 2006
/S/ RUSSELL F. TROMLEY Russell F. Tromley	Director	June 2, 2006
Richard L. Woolworth	Director

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EXHIBIT INDEX

Exhibit Number	Document Description
4.1	Restated Articles of Incorporation of the Company.
4.2	Bylaws of the Company, as amended. Incorporated by reference to Exhibit 3 to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2004, File No. 001-15973.
5.1	Opinion of Stoel Rives LLP.
23.1	Consent of PricewaterhouseCoopers LLP.
23.2	Consent of Stoel Rives LLP (included in Exhibit 5.1).
24.1	Power of Attorney (see page II-6).

EX-4.1

EXHIBIT 4.1

RESTATED ARTICLES OF INCORPORATION

OF

NORTHWEST NATURAL GAS COMPANY

(These Restated Articles of Incorporation of Northwest Natural Gas Company supersede its theretofore existing Restated Articles of Incorporation and all amendments thereto.)

ARTICLE I

The name of this corporation is NORTHWEST NATURAL GAS COMPANY, and its duration shall be perpetual.

ARTICLE II

The purposes of the corporation are to engage in any lawful activity for which corporations may be organized under the Oregon Business Corporation Act.

ARTICLE III

A. The aggregate number of shares of capital stock which the corporation shall have authority to issue is 63,500,000 shares, divided into 3,500,000 shares of Preferred Stock, issuable in series as hereinafter provided, and 60,000,000 shares of Common Stock.

B. A statement of the preferences, limitations and relative rights of each class of capital stock of the corporation, namely, the Preferred Stock and the Common Stock, of the variations in the relative rights and preferences as between series of the Preferred Stock, insofar as the same are fixed by these Restated Articles of Incorporation, and of the authority vested in the board of directors of the corporation to establish series of Preferred Stock and to fix and determine the variations in the relative rights and preferences as between series insofar as the same are not fixed by these Restated Articles of Incorporation, is as follows:

Preferred Stock

1. The shares of the Preferred Stock may be divided into and issued in series. Each series shall be so designated as to distinguish the shares thereof from the shares of all other series of the Preferred Stock and all other classes of capital stock of the corporation. To the extent that these Restated Articles of Incorporation shall not have established series of the Preferred Stock and fixed and determined the variations in the relative rights and preferences as between series, the board of directors shall have authority, and is hereby expressly vested with authority, to divide the Preferred Stock into series and, within the limitations set forth in these Restated Articles of Incorporation and such limitations as may be provided by law, to fix and determine the relative rights and preferences of any series of the Preferred Stock so established. Such action by the board of directors shall be expressed in a resolution or resolutions adopted by it prior to the issuance of shares of each series, which resolution or resolutions shall also set forth the distinguishing designation of the particular series of the Preferred Stock established thereby. Without limiting the generality of the foregoing, authority is hereby expressly vested in the board of directors so to fix and determine with respect to any series of the Preferred Stock:

(a) The rate of dividend and the relative preference of each series in the payment of dividends;

(b) The price at which and the terms and conditions on which shares may be redeemed;

(c) The amount payable upon shares in the event of voluntary and involuntary liquidation and the relative preference of each series on liquidation;

(d) Sinking fund provisions, if any, for the redemption or purchase of shares;

(e) The terms and conditions, if any, on which shares may be converted if the shares of any series are issued with the privilege of conversion; and

(f) Any other relative right or preference as permitted by law.

All shares of the Preferred Stock of the same series shall be identical except that shares of the same series issued at different times may vary as to the dates from which dividends thereon shall be cumulative; and all shares of the Preferred Stock, irrespective of series, shall constitute one and the same class of stock and shall be identical except as to the designation thereof, the date or dates from which dividends on shares thereof shall be cumulative, and the relative rights and preferences set forth above in clauses (a) through (f) of this subdivision, as to which there may be variations between different series. Except as otherwise may be provided by law or by the resolutions establishing any series of Preferred Stock in accordance with the foregoing provisions of this subdivision, whenever the written consent, affirmative vote, or other action on the part of the holders of the Preferred Stock may be required for any purpose, such consent, vote or other action shall be taken by the holders of the Preferred Stock as a single class irrespective of series and not by different series.

2. The holders of shares of the Preferred Stock of each series shall be entitled to receive dividends, when and as declared by the board of directors, out of any funds legally available for the payment of dividends, at the annual rate fixed and determined with respect to each series either by these Restated Articles of Incorporation or in accordance with subdivision III. B. 1., and no more, payable quarterly on the 15th day of February, May, August and November in each year or on such other date or dates as the board of directors shall determine in the resolutions establishing such series. Such dividends shall be cumulative in the case of shares of each series either from the date of issuance of shares of such series or from the first day of the current dividend period within which shares of such series shall be issued, as the board of directors shall determine, so that if dividends on all outstanding shares of each particular series of the Preferred Stock, at the annual dividend rates fixed and determined either by these Restated Articles of Incorporation or in accordance with subdivision III. B. 1., shall not have been paid or declared and set apart for payment for all past dividend periods and for the then current dividend periods, the deficiency shall be fully paid or dividends equal thereto declared and set apart for payment at said rates before any dividends on the Common Stock shall be paid or declared and set apart for payment. No interest, or sum of money in lieu of interest, shall be payable in respect of any dividend payment or payments which may be in arrears.

3. In the event of any dissolution, liquidation or winding up of the corporation, before any distribution or payment shall be made to the holders of the Common Stock, the holders of the Preferred Stock of each series then outstanding shall be entitled to be paid out of the net assets of the corporation available for distribution to its shareholders the respective amounts per share fixed and determined with respect to each series either by these Restated Articles of Incorporation or in accordance with subdivision III. B. 1., and no more. If upon dissolution, liquidation or winding up of the corporation, whether voluntary or involuntary, the net assets of the corporation available for distribution to its shareholders shall be insufficient to pay the holders of all

outstanding shares of Preferred Stock of all series the full amounts to which they shall be respectively entitled as aforesaid, the net assets of the corporation so available for distribution shall be distributed to the holders of Preferred Stock in accordance with the relative preferences of each series of Preferred Stock established either by these Restated Articles of Incorporation or in accordance with subdivision III. B. 1. For the purposes of this subdivision, any dissolution, liquidation or winding up which may arise out of or result from the condemnation or purchase of all or a major portion of the properties of the corporation by (i) the United States Government or any authority, agency or instrumentality thereof (ii) a State of the United States or any political subdivision, authority, agency or instrumentality thereof, or (iii) a district, cooperative or other association or entity not organized for profit, shall be deemed to be an involuntary dissolution, liquidation or winding up; and a consolidation, merger or amalgamation of the corporation with or into any other corporation or corporations shall not be deemed to be a dissolution, liquidation or winding up of the corporation, whether voluntary or involuntary.

4. The holders of shares of the Preferred Stock shall have no right to vote in the election of directors or for any other purpose, except as may be otherwise provided by law or by resolutions establishing any series of Preferred Stock in accordance with subdivision III. B. 1. Holders of Preferred Stock shall be entitled to notice of each meeting of shareholders at which they shall have any right to vote, but shall not be entitled to notice of any other meeting of shareholders.

Common Stock

5. Subject to the limitations set forth in subdivisions III. B. 2. (and subject to the rights of any class of stock hereafter authorized), dividends may be paid upon the Common Stock when and as declared by the board of directors of the corporation out of any funds legally available for the payment of dividends.

6. Subject to the limitations set forth in subdivisions III. B. 3. (and subject to the rights of any other class of stock hereafter authorized), upon any dissolution, liquidation or winding up of the corporation, whether voluntary or involuntary, the net assets of the corporation shall be distributed ratably to the holders of the Common Stock.

7. Except as may be otherwise provided by law or by the resolutions establishing any series of Preferred Stock in accordance with subdivision III. B. 1., the holders of the Common Stock shall have the exclusive right to vote for the election of directors and for all other purposes. In the election of directors of the corporation, every holder of record of any share or shares of the Common Stock of the corporation shall have the right to cast as many votes for one candidate as shall equal the number of such shares multiplied by the number of directors to be elected, or to distribute such number of votes among any two or more candidates for such election.

8. Upon the issuance for money or other consideration of any shares of capital stock of the corporation, or of any security convertible into capital stock of the corporation, no holder of shares of the capital stock, irrespective of the class or kind thereof, shall have any preemptive or other right to subscribe for, purchase or receive any proportionate or other amount of such shares of capital stock, or such security convertible into capital stock, proposed to be issued; and the board of directors may cause the corporation to dispose of all or any of such shares of capital stock, or of any such security convertible into capital stock, as and when said board may determine, free of any such right, either by offering the same to the corporation’s then shareholders or by otherwise selling or disposing of such shares of other securities, as the board of directors may deem advisable.

ARTICLE IV

A. The business and affairs of the corporation shall be managed by a board of directors. Except as provided in subdivision B. below, the number of members of the board, their classifications and terms of office, and the manner of their election and removal shall be as follows:

1. The number of directors shall be that number, not less than nine or more than thirteen, determined from time to time by resolution adopted by affirmative vote of a majority of the entire board of directors. The directors shall be divided into three classes, designated Class I, Class II, and Class III. Each class shall consist, as nearly as possible, of one-third of the total number of directors. At the 1984 annual meeting of shareholders, Class I directors shall be elected for a one-year term, Class II directors for a two-year term, and Class III directors for a three-year term. At each succeeding annual meeting of shareholders, successors to directors whose terms expire at that annual meeting shall be of the same class as the directors they succeed, and shall be elected for three-year terms. If the number of directors should be changed by resolution of the board of directors, any increase or decrease shall be apportioned among the classes so as to maintain the number of directors in each class as nearly equal as possible, but in no case shall a decrease in the number of directors shorten the term of any incumbent director.

2. A director shall hold office until the annual meeting for the year in which his or her term shall expire and until his or her successor shall have been elected and qualified, subject, however, to prior death, resignation, retirement or removal from office. Any newly created directorship resulting from an increase in the number of directors and any other vacancy on the board of directors, however caused, may be filled by the affirmative vote of a majority of the directors then in office, although less than a quorum, or by a sole remaining director.

3. One or more of the directors may be removed with or without cause by the affirmative vote of the holders of not less than two-thirds of the shares entitled to vote thereon at a meeting of the shareholders called expressly for that purpose; provided, however, that for as long as the corporation shall have cumulative voting, if fewer than all the directors should be candidates for removal, no one of them shall be removed if the votes cast against his or her removal would be sufficient to elect him or her if then cumulatively voted at an election of the class of directors of which he or she shall be a part.

4. No person, except those persons nominated by the board, shall be eligible for election as a director at any annual or special meeting of shareholders unless a written request that his or her name be placed in nomination shall be received from a shareholder of record entitled to vote at such election by the secretary of the corporation not later than the latter of (a) the thirtieth day prior to the date fixed for the meeting, or (b) the tenth day after the mailing of notice of that meeting, together with the written consent of the nominee to serve as a director.

B. Notwithstanding the provisions of subdivision A. above, whenever the holders of any one or more classes of the capital stock of the corporation shall have the right, voting separately as a class or classes, to elect directors at an annual or special meeting of shareholders, the election, term of office, filling of vacancies and other features of such directorships shall be governed by the provisions of these Restated Articles of Incorporation applicable thereto. Directors so elected shall not be divided into classes unless expressly provided by such provisions, and during their prescribed terms of office, the board of directors shall consist of such directors in addition to the directors determined as provided in subdivision A. above.

C. This Article IV may not be repealed or amended in any respect unless such action shall be approved by the affirmative vote of the holders of not less than two-thirds of the shares entitled to vote at an election of directors determined as provided in subdivision A. above, at a meeting of the shareholders called expressly for that purpose.

ARTICLE V

A. For purposes of this Article V:

1. The term “Affiliate”, as used to indicate a relationship with a specified “Persons” (as hereinafter defined), shall mean a Person that directly or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, the Person specified.

2. The term “Associate”, as used to indicate a relationship with a specified Person, shall mean (a) any Person (other than the corporation) of which such specified Person is a director, officer, partner, trustee, guardian, fiduciary or official or is, directly or indirectly, the beneficial owner of 10% or more of any class of equity securities or any beneficial interest, (b) any Person who is a director, officer, partner, trustee, guardian, fiduciary or official or is, directly or indirectly, the beneficial owner of 10% or more of any class of equity securities or any beneficial interest of or in such specified Person (other than the corporation), and (c) any relative or spouse of such specified Person, or any relative of such spouse who has the same home as such specified Person.

3. The term “Beneficial Owner” shall have the meaning set forth in Rule 13d-3 of the General Rules and Regulations under the Securities Exchange Act of 1934 as in effect on April 9, 1984; provided, however, that, notwithstanding the provisions of such Rule, a Person shall be deemed to be the Beneficial Owner of any share of the capital stock of the corporation that such Person shall have the right to acquire at any time pursuant to any agreement, contract, arrangement or understanding, or upon exercise of conversion rights, warrants or options, or otherwise, and any such share of capital stock shall be deemed to be outstanding for purposes of subdivision V.A.9.

4. The term “Business Transaction” shall include, without limitation, (a) any merger, consolidation or plan of exchange of the corporation, or any Person controlled by or under common control with the corporation, with or into any “Related Person” (as hereinafter defined), (b) any merger, consolidation or plan of exchange of a Related Person with or into the corporation or any Person controlled by or under common control with the corporation, (c) any sale, lease, exchange, transfer or other disposition (in one transaction or a series of transactions) including without limitation a mortgage or any other security device, of all or any “Substantial Part” (as hereinafter defined) of the property and assets of the corporation, or any Person controlled by or under common control with the corporation, to or with a Related Person, (d) any purchase, lease, exchange, transfer or other acquisition (in one transaction or a series of transactions), including without limitation a mortgage or any other security device, of all or any Substantial Part of the property and assets of a Related Person, by or with the corporation or any Person controlled by or under common control with the corporation, (e) any recapitalization of the corporation that would have the effect of increasing the voting power of a Related Person, (f) the issuance, sale, exchange or other disposition of any securities of the corporation, or of any Person controlled by or under common control with the corporation, by the corporation or by any Person controlled by or under common control with the corporation, (g) any liquidation, spinoff, splitoff, splitup or dissolution of the corporation, and (h) any agreement, contract or other arrangement providing for any of the transactions described in this subdivision.

5. The term “Continuing Director” shall mean a director who was a director of the corporation on April 9, 1984 and a director who shall become a director subsequent thereto whose election, or whose nomination for election by the shareholders, shall have been approved by a vote of a majority of the then Continuing Directors.

6. The term “Highest Purchase Price” shall mean, with respect to the shares of any class or series of the capital stock of the corporation, the highest amount of consideration paid by a Related Person for a share of the same class and series at any time regardless of whether the share was acquired before or after such Related Person became a Related Person; provided, however, that the Highest Purchase Price shall be appropriately adjusted to reflect the occurrence of any reclassification, recapitalization, stock split, reverse stock split or other readjustment in the number of outstanding shares of that class or series, or the declaration of a stock dividend thereon. The Highest Purchase Price shall include any brokerage commissions, transfer taxes and soliciting dealers’ fees paid by such Related Person with respect to any shares of the capital stock acquired by such Related Person.

7. The term “Other Consideration” shall include, without limitation, capital stock to be retained by the shareholders of the corporation in a Business Transaction in which the corporation shall be the survivor.

8. The term “Person” shall mean any natural person, corporation, partnership, trust, firm, association, government, governmental. agency or any other entity whether acting in an individual, fiduciary or other capacity.

9. The term “Related Person” shall mean (a) any Person which, together with its Affiliates and Associates, shall be the Beneficial Owner in the aggregate of 10 percent or more of the capital stock of the corporation, and (b) any Affiliate or Associate (other than the corporation or a wholly owned subsidiary of the corporation) of any such Person. Two or more Persons acting in concert for the purpose of acquiring, holding or disposing of the capital stock of the corporation shall be deemed to be a “Related Person”. A Related Person shall be deemed to have acquired a share of capital stock at the time when such Related Person became the Beneficial Owner thereof. With respect to the shares of the capital stock of the corporation owned by any Related Person, if the price paid for such shares cannot be determined by a majority of the Continuing Directors, the price so paid shall be deemed to be the market price of the shares in question at the time when such Related Person became the Beneficial Owner thereof.

10. The term “Substantial Part” shall mean 10% or more of the fair market value of the total assets of a Person, as reflected on the most recent balance sheet of such Person available to the Continuing Directors on the date of mailing of the notice of the meeting of shareholders called for the purpose of voting with respect to a Business Transaction involving the assets constituting any such Substantial Part.

B. The corporation shall not enter into any Business Transaction with a Related Person or in which a Related Person shall have an interest (except proportionately as a shareholder of the corporation) without first obtaining both (1) the affirmative vote of the holders of not less than two-thirds of the outstanding shares of the capital stock of the corporation not held by such Related Person, and (2) the determination of a majority of the Continuing Directors that the cash or fair market value of the property, securities or Other Consideration to be received per share by the holders, other than such Related Person, of the shares of each class or series of the capital stock of the corporation in such Business Transaction shall not be less than the Highest Purchase Price paid by such Related Person in acquiring any of its holdings of shares of the same class or series, unless the Continuing Directors by a majority vote shall either (a) have expressly approved the acquisition of the shares of the capital stock of the corporation that caused such Related Person to become a Related Person, or (b) have expressly approved such Business Transaction.

C. For the purposes of this Article V, a majority of the Continuing Directors shall have the power to

make a good faith determination, on the basis of information known to them, of: (1) the number of shares of capital stock of the corporation of which any Person shall be the Beneficial Owner, (2) whether a Person is an Affiliate or Associate of another Person, (3) whether a Person has an agreement, contract, arrangement or understanding with another Person as to the matters referred to in subdivision V.A.3. or clause (h) of subdivision V.A.4., (4) the Highest Purchase Price paid by a Related Person for shares of any class or series of the capital stock, (5) whether the assets subject to any Business Transaction constitute a Substantial Part, (6) whether any Business Transaction is one in which a Related Person has an interest (except proportionately as a shareholder of the corporation), and (7) such other matters with respect to which a determination may be required under this Article V.

D. In determining whether to give their approval as provided in subdivision V.B., the Continuing Directors shall give due consideration to all relevant factors involved, including, without limitation, (1) the value of the corporation in a freely negotiated transaction and its future value as an independent entity, (2) the recognition of gain or loss to the corporation for tax purposes or the postponement of such recognition in a tax-free transaction, (3) the anticipated developments of the business of the corporation not yet reflected in the price of its shares, and (4) the impact on employees, customers, suppliers and the public generally within the geographical area it serves.

E. This Article V may not be repealed or amended in any respect unless such action shall be approved by the affirmative vote of the holders of not less than two-thirds of the capital stock of the corporation not held by a Related Person at a meeting of the shareholders called expressly for that purpose.

ARTICLE VI

No director of the corporation shall be personally liable to the corporation or its shareholders for monetary damages for conduct as a director; provided that this Article VI shall not eliminate the liability of a director for any act or omission for which such elimination of liability is not permitted under the Oregon Business Corporation Act. No amendment to the Oregon Business Corporation Act that further limits the acts or omissions for which elimination of liability is permitted shall affect the liability of a director for any act or omission which occurs prior to the effective date of such amendment.

ARTICLE VII

The corporation shall indemnify to the fullest extent then permitted by law any person who is made, or threatened to be made, a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative, investigative or otherwise (including an action, suit or proceeding by or in the right of the corporation) by reason of the fact that the person is or was a director or officer of the corporation or is or was serving at the request of the corporation as a director or officer of another corporation, partnership, joint venture, trust or other enterprise against all judgments, amounts paid in settlement, fines and such expenses (including attorneys’ fees), actually and reasonably incurred in connection therewith. This Article shall not be deemed exclusive of any other provisions for indemnification of directors and officers that may be included in any statute, bylaw, agreement, vote of shareholders or directors or otherwise, both as to action in any official capacity and as to action in another capacity while holding an office.

As amended May 31, 2006.

EX-5.1

EXHIBIT 5.1

[STOEL RIVES LLP LETTERHEAD]

June 13, 2006

Board of Directors

Northwest Natural Gas Company

220 N.W. Second Avenue

Portland, Oregon 97209

We have acted as counsel for Northwest Natural Gas Company (the “Company”) in connection with the filing with the Securities and Exchange Commission of a Registration Statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended, covering 200,000 shares of Common Stock (the “Shares”) issuable in connection with the Company’s Employee Stock Purchase Plan (the “Plan”). We have reviewed the corporate actions of the Company in connection with this matter and have examined those documents, corporate records, and other instruments we deemed necessary for the purposes of this opinion.

Based on the foregoing, it is our opinion that all requisite action necessary to make the Shares validly issued, fully paid and non-assessable will have been taken when:

(1) the issuance of the Shares 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; and

(2) the Shares shall have been issued in accordance with the Plan.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement.

Very truly yours,

/s/ STOEL RIVES LLP

STOEL RIVES LLP

EX-23.1

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated February 28, 2006 relating to the financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, which appears in the 2005 Annual Report to Shareholders of Northwest Natural Gas Company (the Company), on Form 10-K for the year ended December 31, 2005. We also consent to the incorporation by reference of our report dated February 28, 2006 relating to the financial statement schedule, which appears in such Annual Report on Form 10-K.

/s/ PRICEWATERHOUSECOOPERS LLP

PricewaterhouseCoopers LLP

Portland, Oregon

June 13, 2006