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 19, 2015

Comcast Corporation

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (215) 286-1700

(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 (see General Instruction A.2. below):

On May 27, 2015 Comcast Corporation (“Comcast”) has consummated the issuance and sale of $1,500,000,000 aggregate principal amount of its 3.375% Notes due 2025, $800,000,000 aggregate principal amount of its 4.400% Notes due 2035 and $1,700,000,000 aggregate principal amount of its 4.600% Notes due 2045 (collectively, the “Notes”), pursuant to an underwriting agreement dated May 19, 2015 among Comcast, the Guarantors (defined below) and Citigroup Global Markets Inc., Goldman, Sachs & Co. and Morgan Stanley & Co. LLC, as representatives of the several underwriters named therein. The Notes were issued pursuant to an Indenture dated as of September 18, 2013 (the “Indenture”) among Comcast, the guarantors named therein and The Bank of New York Mellon, as trustee (the “Trustee”), and an officers’ certificate issued pursuant thereto. The Notes are guaranteed on an unsecured and unsubordinated basis by Comcast Cable Communications, LLC, Comcast Cable Holdings, LLC, Comcast MO Group, Inc., Comcast MO of Delaware, LLC and NBCUniversal Media, LLC (the “Guarantors”).

The Notes are being offered pursuant to Comcast’s Registration Statement on Form S-3 filed on September 18, 2013, as amended on February 19, 2014 (Reg. No. 333-191239), including the prospectus contained therein, and a related prospectus supplement dated May 19, 2015.

The material terms and conditions of the Notes are set forth in the Form of Officers’ Certificate filed herewith as Exhibit 4.1 and incorporated by reference herein and in the Indenture filed as Exhibit 4.3 to Comcast’s Registration Statement on Form S-3 filed on September 18, 2013, as amended on February 19, 2014.

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.