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 5, 2011

NOBLE ENERGY, INC.

(Exact name of Registrant as specified in its charter)

Registrant’s telephone number, including area code: (281) 872-3100

(Former name, former address and former fiscal year, 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:

Item 1.01. Entry into a Material Definitive Agreement.

On December 5, 2011, Noble Energy, Inc. (the “Company”) entered into an Underwriting Agreement (the “Underwriting Agreement”) among the Company and J.P. Morgan Securities LLC and Citigroup Global Markets Inc., as representatives of the several underwriters named therein (the “Underwriters”), with respect to the issuance and sale of $1,000,000,000 aggregate principal amount of 4.15% notes due 2021 (the “Notes”). The Notes have been registered under the Securities Act of 1933 (the “Act”) pursuant to a Registration Statement on Form S-3 (No. 333-157406) which was filed with the Securities and Exchange Commission (the “SEC”) and became automatically effective on February 19, 2009. The terms of the Notes are further described in the Company’s prospectus supplement dated December 5, 2011, as filed with the SEC under Rule 424(b)(2) of the Act on that date. The closing of the sale of the Notes occurred on December 8, 2011. The Notes are unsubordinated and unsecured obligations of the Company. The net proceeds from the sale of the Notes, after deducting the underwriting discounts and estimated offering expenses, were approximately $991.3 million.

The Notes are governed by the terms of an Indenture dated as of February 27, 2009 between the Company and Wells Fargo Bank, National Association as trustee (the “Trustee”), as supplemented by the Third Supplemental Indenture dated as of December 8, 2011 between the Company and the Trustee.

The Underwriting Agreement includes customary representations, warranties and covenants by the Company. It also provides for customary indemnification by each of the Company and the respective Underwriters against certain liabilities arising out of or in connection with sale of the Notes and for customary contribution provisions in respect of those liabilities.

A copy of the Underwriting Agreement and the Third Supplemental Indenture have been filed as Exhibits 1.1 and 4.1, respectively, to this report and are incorporated herein by reference.

Some of the Underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with the Company or its affiliates, for which they have received, or may in the future receive, customary fees and commissions for those transactions.

Item 9.01. Financial Statements and Exhibits.

SIGNATURE

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

INDEX TO EXHIBITS