Exhibit No. 32.

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with this report of Questar Pipeline Company (the Company) on Form 10-Q for the period ended March 31, 2010, as filed with the Securities and Exchange Commission on the date hereof (the Report), R. Allan Bradley, President and Chief Executive Officer of the Company, and Richard J. Doleshek, Executive Vice President and Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to the best of his knowledge:

(1)

The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934; and

(2)

The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

QUESTAR PIPELINE COMPANY

May 7, 2010

/s/R. Allan Bradley

R. Allan Bradley

President and Chief Executive Officer

May7, 2010

/s/Richard J. Doleshek

Richard J. Doleshek

Executive Vice President and Chief Financial Officer

QUESTAR PIPELINE CO 10-Q