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Pricing Supplement Dated October 3, 2001                         Rule 424(b)(5)
(To Prospectus dated October 2, 2001)                        File No. 333-69210
No. 001
CUSIP No. 74835WAA3

                               QUESTAR GAS COMPANY
                     Fixed Rate Medium-Term Notes, Series D

     We are hereby offering to sell Notes having the terms specified below to
you with the assistance of Merrill Lynch & Co., Banc One Capital Markets, Inc.
and U.S. Bancorp Piper Jaffray, acting as agents, at an offering price of 100%
of the Principal Amount.

PRINCIPAL AMOUNT:            $60,000,000  ORIGINAL ISSUE DATE: October 9, 2001

AGENTS' DISCOUNT OR COMMISSION: $375,000  STATED MATURITY DATE: October 1, 2012

NET PROCEEDS TO COMPANY:     $59,625,000  INTEREST PAYMENT DATES: April 1st and
                                          October 1st, commencing April 1, 2002.
INTEREST RATE: 6.30% per annum

OPTIONAL REDEMPTION:

     The Notes may be redeemable as a whole or in part, at the option of the
     Company at any time, at a redemption price equal to the greater of (i) 100%
     of the principal amount of such Notes and (ii) the sum of the present
     values of the remaining scheduled payments of principal and interest
     thereon (exclusive of interest accrued to the date of redemption)
     discounted to the redemption date on a semiannual basis (assuming a 360-day
     year consisting of twelve 30-day months) at the Treasury Rate plus
     twenty-five (25) basis points, plus in each case accrued interest thereon
     to the date of redemption.

     "Treasury Rate" means, with respect to any redemption date, the rate per
     annum equal to the semiannual equivalent yield to maturity or interpolated
     (on a date count basis) of the Comparable Treasury Issue, assuming a price
     for the Comparable Treasury Issue (expressed as a percentage of its
     principal amount) equal to the Comparable Treasury Price for such
     redemption date.

     "Comparable Treasury Issue" means the United States Treasury security
     selected by an Independent Investment Banker as having an actual or
     interpolated maturity comparable to the remaining term of the Notes to be
     redeemed that would be utilized, at the time of selection and in accordance
     with customary financial practice, in pricing new issues of corporate debt
     securities of a comparable maturity to the remaining term of such Notes.

     "Independent Investment Banker" means one of the Reference Treasury Dealers
     appointed by the Trustee after consultation with the Company.

     "Comparable Treasury Price" means, with respect to any redemption date, (i)
     the average of the Reference Treasury Dealer Quotations for such redemption
     date, after excluding the highest and lowest such Reference Treasury Dealer
     Quotations, or (ii) if the Trustee obtains fewer than four such Reference
     Treasury Dealer Quotations, the average of all such quotations. "Reference
     Treasury Dealer Quotations" means, with respect to each Reference Treasury
     Dealer and any redemption date, the average, as determined by the Trustee,
     of the bid and asked prices for the Comparable Treasury Issue (expressed in
     each case as a percentage of its principal amount) quoted in writing to the
     Trustee by such Reference Treasury Dealer at 3:30 p.m. New York time on the
     third business day preceding such redemption date.
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Questar Gas Company - Fixed Rate Medium-Term Notes, Series D

Pricing Supplement Dated October 3, 2001

No. 001

OPTIONAL REDEMPTION CONTINUED:

     "Reference Treasury Dealer" means each of Merrill Lynch Government
     Securities Inc., Banc One Capital Markets, Inc. and U.S. Bancorp Piper
     Jaffray, or their affiliates which are U.S. Government securities
     dealers, and their respective successors; provided, however, that if any
     of the foregoing or their affiliates shall cease to be a primary U.S.
     Government securities dealer in The City of New York (a "Primary
     Treasury Dealer"), the Company shall substitute therefor another Primary
     Treasury Dealer.

     Notice of any redemption will be mailed at least 30 days but not more than
     60 days before the redemption date to each holder of Notes to be redeemed.

     Unless the Company defaults in payment of the redemption price, on and
     after the redemption date interest will cease to accrue on the Notes or
     portions thereof called for redemption.


REPAYMENT:

     Except as set forth under the redemption provisions above, the Notes may
     not be repaid prior to the Stated Maturity Date.


OTHER PROVISIONS:

     The Notes are offered at 100% of the Principal Amount.

     The Notes are offered in Book-Entry form.

<Table>
<Caption>
NAME OF AGENT:                     PRINCIPAL AMOUNT
                                
     Merrill Lynch & Co.              $20,000,000

     Banc One Capital Markets, Inc.    20,000,000

     U.S. Bancorp Piper Jaffray        20,000,000
                                      -----------
                                      $60,000,000
                                      ===========
</Table>