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 (Date of earliest event reported) December 7, 2010

SOUTHWEST GAS CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (702) 876-7237

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:

On December 7, 2010, Southwest Gas Corporation (the “Company”) issued a press release announcing that it has priced a public offering of $125 million aggregate principal amount of its 4.45% Senior Notes due 2020 (the “Notes”). The Notes were offered pursuant to a Prospectus Supplement dated December 7, 2010 to the Prospectus dated December 23, 2008, filed as part of the Registration Statement on Form S-3 (File No. 333-156420) that became effective when filed with the Securities and Exchange Commission on December 23, 2008.

In connection with the offering of the Notes, the Company entered into an Underwriting Agreement, dated December 7, 2010, with U.S. Bancorp Investments, Inc. and KeyBanc Capital Markets Inc., as representatives of the underwriters named therein (the “Underwriting Agreement”). In addition, the Company entered into a base Indenture with respect to the Notes with The Bank of New York Mellon Trust Company, N.A., as Trustee (the “Base Indenture”).

The Underwriting Agreement and the Base Indenture are attached hereto as Exhibit 1.1 and Exhibit 4.1, respectively, and are incorporated herein by reference. The Company’s press release is furnished as Exhibit 99.1 and incorporated herein by reference.

(d) Exhibits

SIGNATURES

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 hereunto duly authorized.

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