UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

The Securities Exchange Act of 1934

Date of Report – October 15, 2010

(Date of earliest event reported)

QUESTAR CORPORATION

(Exact name of registrant as specified in its charter)

180 East 100 South Street, P.O. Box 45433 Salt Lake City, Utah 84145-0433

(Address of principal executive offices)

Registrant's telephone number, including area code (801) 324-5699

                                  Not Applicable                                  

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

[  ]  Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17

       CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17

       CFR 240.13e-4(c))

This Current Report on Form 8-K dated October 15, 2010, of Questar Corporation (the Company) is filed solely to provide Exhibit 101 in accordance with Rule 405(a)(2) of Regulation S-T that was not included in a Current Report on Form 8-K dated September 30, 2010. Exhibit 101 includes information about the Company in Extensible Business Reporting Language (XBRL). No other changes have been made to the Company’s Form 8-K dated September 30, 2010 (Original Filing). This Current Report on Form 8-K does not change any other information set forth in the Original Filing and the Company has not updated disclosures included therein to reflect any events that occurred subsequent to September 30, 2010.

Users of this data are advised that pursuant to Rule 406T of Regulation S-T, these interactive data files are deemed not filed or part of a registration statement or prospectus for purposes of sections 11 or 12 of the Securities Act of 1933, and are deemed not filed for purposes of section 18 of the Securities and Exchange Act of 1934, and otherwise are not subject to liability.

Section 9 - Financial Statements and Exhibits

Item 9.01

Financial Statements and Exhibits.

(d)

Exhibits.

Exhibit No.

Exhibit

101.INS

XBRL Instance.

101.SCH

XBRL Taxonomy.

101.LAB

XBRL Labels.

101.PRE

XBRL Presentation.

101.CAL

XBRL Calculations.

101.DEF

XBRL Definitions.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Questar Corporation

   (Registrant)

October 15, 2010

/s/Martin H. Craven

Martin H. Craven

Vice President, Chief Financial Officer

and Treasurer

List of Exhibits:

Exhibit No.

Exhibit

101.INS

XBRL Instance.

2

101.SCH

XBRL Taxonomy.

101.LAB

XBRL Labels.

101.PRE

XBRL Presentation.

101.CAL

XBRL Calculations.

101.DEF

XBRL Definitions.

3