Filing under Rule 433

Dated December 12, 2006

Registration No. 333-112604

$160,000,000

NORTHWEST NATURAL GAS COMPANY

Secured Medium-Term Notes, Series B

(A Series of First Mortgage Bonds)

and

Unsecured Medium-Term Notes, Series B

Due from Nine Months to 30 Years from Date of Issue

 

CUSIP No.: 66765R BW5   Secured   X   Unsecured            Principal amount ($): $25,000,000   Issue price (%): 100%   Proceeds to Company ($): $24,843,750   Repayable at the option of holder: Yes          No   X     Repayment Date: Not Applicable   Repayment Price: Not Applicable   Election Period: Not Applicable   Selling Agent(s): UBS Securities LLC   Type of Transaction: Principal Transaction   Ratings: A2/AA- (S/S)		Stated interest rate (%): 5.15%   Maturity date: December 15, 2016   Original issue date: December 15, 2006   Interest payment dates: June 1 and December 1, commencing June 1, 2007   Redeemable: Yes   X   No            In whole            In whole or in part   X     Fixed redemption price: Yes          No   X     Initial redemption date: Not Applicable   Initial redemption price: Not Applicable   Reduction Percentage: Not Applicable   Redemption limitation date: Not Applicable   Make-Whole Redemption Price: Yes   X   No            Make-Whole Spread: 0.15%

The issuer has filed a registration statement (including a prospectus) with the Securities and Exchange Commission for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the Securities and Exchange Commission for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the Securities and Exchange Commission’s Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling UBS Securities LLC toll-free at 1-888-722-9555, ext 1088.