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) September 29, 2011

WESTAR ENERGY, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (785) 575-6300

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:

WESTAR ENERGY, INC.

On September 29, 2011, we entered into a new revolving credit facility. The new facility matures on September 29, 2016. So long as there is no default under the facility, we may elect to extend the facility for up to an additional two years, subject to lender participation. The facility allows us to borrow up to an aggregate of $730.0 million, including letters of credit up to a maximum aggregate amount of $730.0 million. So long as there is no default under the facility, we may elect to increase the aggregate amount of borrowings under the facility to $1.0 billion by increasing the commitment of one or more lenders who have agreed to such increase, or by adding a new lender or lenders to the facility, or by a combination of both existing and new lenders. All borrowings under the facility are secured by first mortgage bonds of our wholly owned subsidiary, Kansas Gas and Electric Company. We may elect to release this security at any time that our senior unsecured debt is rated investment grade by at least two of S&P, Moody’s and Fitch.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information set forth under Item 1.01 is incorporated herein by reference.

Forward-looking statements: Certain matters discussed in this Current Report on Form 8-K are “forward-looking statements.” The Private Securities Litigation Reform Act of 1995 has established that these statements qualify for safe harbors from liability. Forward-looking statements may include words like “believe,” “anticipate,” “target,” “expect,” “pro forma,” “estimate,” “intend,” “guidance” or words of similar meaning. Forward-looking statements describe future plans, objectives, expectations or goals. Although Westar Energy believes that its expectations are based on reasonable assumptions, all forward-looking statements involve risk and uncertainty. The factors that could cause actual results to differ materially from these forward-looking statements include those discussed herein as well as (1) those discussed in the company’s Annual Report on Form 10-K for the year ended Dec. 31, 2010 (a) under the heading, “Forward-Looking Statements,” (b) in ITEM 1. Business, (c) in ITEM 1A. Risk Factors, (d) in ITEM 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations, and (e) in ITEM 8. Financial Statements and Supplementary Data: Notes 13 and 15;

(2) those discussed in the company’s Quarterly Report on Form 10-Q filed Aug. 4, 2011 (a) in ITEM 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations and (b) in Part 1, Financial Information, ITEM 1. Financial Statements: Notes 8 and 9; and (3) other factors discussed in the company’s filings with the Securities and Exchange Commission. Any forward-looking statement speaks only as of the date such statement was made, and the company does not undertake any obligation to update any forward-looking statement to reflect events or circumstances after the date on which such statement was made.

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 hereunto duly authorized.

EXHIBIT INDEX