UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Form 8-K
CURRENT REPORT

SOUTHWEST GAS CORPORATION
(Exact name of registrant as specified in its charter)

Item 12. Results of Operations and Financial Condition.

On July 29, 2004, Southwest Gas Corporation (the Company) released summary financial information to the general public, including the investment community, regarding the Company’s operating performance for the quarter, six, and twelve months ended June 30, 2004. A copy of the Company’s press release and summary financial information is attached hereto as Exhibit 99.

This Form 8-K and the attached exhibit are provided under Item 12 of Form 8-K and are furnished to, but not filed with, the Securities and Exchange Commission.

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.

EXHIBIT INDEX

July 29, 2004
Media Contact: Roger Buehrer, Las Vegas, NV (702) 876-7132
Shareholder Contact: Ken Kenny, Las Vegas, NV (702) 876-7237
SWX-NYSE
For Immediate Release

SOUTHWEST GAS CORPORATION
REPORTS SECOND QUARTER RESULTS

Las Vegas — Southwest Gas Corporation recorded a net loss of $0.24 per share for the second quarter of 2004, a $0.12 decrease from the $0.12 per share loss reported for the second quarter of 2003. Net loss for the second quarter of 2004 was $8.4 million compared to the 2003 second quarter net loss of $4.1 million. Due to the seasonal nature of the business, net losses during the second and third quarters are normal and not generally indicative of earnings for a complete 12-month period.

According to Jeffrey W. Shaw, Chief Executive Officer, “Second quarter results, although lower than last year, were in line with internal expectations. The primary reason for the decline was higher operating costs relative to the increase in operating margin. The Company added a record 74,000 customers, plus 9,000 from an acquisition, over the last 12 months. Operating margin, however only increased modestly due to warmer-than-normal temperatures experienced in April and May. Operating costs, on the other hand, trended upward due to the combined impacts of customer growth, inflation, and regulatory compliance.” Shaw reiterated that “the long-term success of Southwest Gas depends upon taking advantage of customer growth opportunities.”

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For the twelve months ended June 30, 2004, consolidated net income was $49.7 million, or $1.45 per basic share, compared to $43.1 million, or $1.29 per basic share, during the twelve-month period ended June 30, 2003.

Natural Gas Operations Segment Results

Second Quarter

Operating margin, defined as operating revenues less the cost of gas sold, increased approximately $3 million, or three percent, in the second quarter of 2004 compared to the second quarter of 2003. Customer growth contributed an incremental $3 million in operating margin during the quarter. Rate relief in California added $2 million in margin, while differences in heating demand caused by weather variations between periods accounted for a $2 million decrease. During the last 12 months, the Company added 74,000 customers, an increase of five percent. Another 9,000 customers were added in October 2003 with the acquisition of Black Mountain Gas Company.

Operating expenses for the quarter increased $9.4 million, or nine percent, compared to the second quarter of 2003 primarily due to incremental costs associated with expanding and upgrading the gas system to accommodate record customer growth. Additional factors include general cost increases and higher employee-related and regulatory costs. Despite an increase in outstanding debt, net financing costs were virtually unchanged between periods due to interest savings generated from debt and preferred securities instrument refinancings and a reduction in interest costs associated with the purchased gas adjustment account balance.

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Twelve Months to Date

Operating margin increased $43 million, or eight percent, between periods. Differences in heating demand caused by weather variations between periods resulted in a $20 million margin increase as warmer-than-normal temperatures were experienced during both periods. During the current period, operating margin was negatively impacted by $15 million, while in the prior period the negative impact was $35 million. Customer growth contributed an incremental $17 million and California rate relief added $9 million. Conservation, energy efficiency and other factors partially offset these improvements.

Operating expenses increased $22.6 million, or five percent, primarily reflecting incremental costs associated with servicing a growing customer base. Net financing costs decreased $1.7 million, or two percent, primarily due to interest savings generated from the refinancing of industrial development revenue bonds and preferred securities instruments.

Other income decreased $10.5 million between periods. The prior period reflected income of $13.6 million associated with the timing of merger-related insurance recoveries, net of costs. The current period includes a $2.3 million improvement in returns on long-term investments.

Southwest Gas Corporation provides natural gas service to approximately 1,560,000 customers in Arizona, Nevada and California. Its service territory is centered in the fastest-growing region of the country.

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This press release may contain statements which constitute “forward-looking statements” within the meaning of the Securities Litigation Reform Act of 1995 (Reform Act). All such forward-looking statements are intended to be subject to the safe harbor protection provided by the Reform Act. A number of important factors affecting the business and financial results of the Company could cause actual results to differ materially from those stated in the forward-looking statements. These factors include, but are not limited to, the impact of weather variations on customer usage, customer growth rates, natural gas prices, the effects of regulation/deregulation, the timing and amount of rate relief, changes in gas procurement practices, changes in capital requirements and funding, the impact of conditions in the capital markets on financing costs, changes in construction expenditures and financing, acquisitions, and competition.

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SOUTHWEST GAS CONSOLIDATED EARNINGS DIGEST
(In thousands, except per share amounts)

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SOUTHWEST GAS CORPORATION
SUMMARY UNAUDITED OPERATING RESULTS
(In thousands, except per share amounts)

SOUTHWEST GAS CORPORATION
SELECTED STATISTICAL DATA
JUNE 30, 2004

GAS OPERATIONS SEGMENT

(1)  Estimated amounts based on rate case settlements.