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): May 5, 2011 (May 4, 2011)

PLAINS EXPLORATION & PRODUCTION COMPANY

(Exact name of registrant as specified in charter)

001-31470

(Commission File No.)

700 Milam, Suite 3100

Houston, Texas 77002

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s telephone number, including area code: (713) 579-6000

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 May 4, 2011, Plains Exploration & Production Company (“PXP”) entered into Amendment No. 2 to its Amended and Restated Credit Agreement with JPMorgan Chase Bank, N.A. as administrative agent and the lenders party thereto (the “Second Amendment”), which amends PXP’s senior revolving credit facility that closed on August 3, 2010 (the “Credit Facility”). The Second Amendment amends the Credit Facility to extend the maturity date from August 3, 2015 to May 4, 2016 and lowers the rate at which borrowings can be made.

Amounts borrowed under the Credit Facility, as amended, bear an interest rate, at PXP’s election, equal to either: (i) the Eurodollar rate, which is based on LIBOR, plus an additional variable amount ranging from 1.50% to 2.50%; (ii) a variable amount ranging from 0.50% to 1.50% plus the greater of (1) the prime rate, as determined by JPMorgan Chase Bank, (2) the federal funds rate, plus  ¹/2 of 1%, and (3) the adjusted LIBOR plus 1%; or (iii) the overnight federal funds rate plus an additional variable amount ranging from 1.50% to 2.50% for swingline loans. The additional variable amount of interest payable on outstanding borrowings is based on the utilization rate as a percentage of the total amount of funds borrowed under the Credit Facility to the borrowing base. Letter of credit fees under the Credit Facility are based on the utilization rate and range from 1.50% to 2.50%. Commitment fees range from 0.375% to 0.50% for amounts available for borrowing. The other terms and conditions of the Credit Facility remained the same.

The foregoing description of the Second Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Second Amendment, which is filed as Exhibit 4.1 hereto and incorporated by reference herein.

On May 5, 2011, PXP issued a press release announcing first quarter 2011 results. The press release is furnished herewith as Exhibit 99.1 and is incorporated by reference herein. In connection with such release, PXP has prepared investor slides, which are furnished herewith as Exhibit 99.2 and are incorporated by reference herein.

The information presented under this Item 2.02 shall not be deemed “filed” under the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as may be expressly set forth by specific reference in such a filing.

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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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EXHIBIT INDEX

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