UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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): February 18, 2015

Waste Management, Inc.

(Exact Name of Registrant as Specified in Charter)

Registrant’s Telephone number, including area code: (713) 512-6200

(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:

Item 1.01 Entry Into a Material Definitive Agreement.

Item 8.01 Other Events.

On February 18, 2015, Waste Management, Inc. (the “Company”) commenced an underwritten public offering of $600,000,000 aggregate principal amount of its 3.125% Senior Notes due 2025, $450,000,000 aggregate principal amount of its 3.900% Senior Notes due 2035 and $750,000,000 aggregate principal amount of its 4.100% Senior Notes due 2045 (collectively, the “Notes”) under the Company’s Registration Statement on Form S-3 (No. 333-184157) (the “Registration Statement”). The Notes, which will be fully and unconditionally guaranteed by the Company’s wholly owned subsidiary Waste Management Holdings, Inc. (“WM Holdings”), will be sold pursuant to an underwriting agreement (the “Underwriting Agreement”) entered into on February 18, 2015 among the Company and WM Holdings and Credit Suisse Securities (USA) LLC, Deutsche Bank Securities Inc., Goldman, Sachs & Co. and J.P. Morgan Securities LLC as representatives of the several underwriters named therein.

The Underwriting Agreement includes the terms and conditions for the issuance and sale of the Notes, indemnification and contribution obligations and other terms and conditions customary in agreements of this type. Certain of the underwriters and their respective affiliates have, from time to time, performed, and may in the future perform, various financial advisory, investment banking and commercial services for the Company, for which they have received or will receive customary fees and expense reimbursements.

Closing of the issuance and sale of the Notes is expected to occur on February 26, 2015. The Notes will be issued under an indenture dated as of September 10, 1997, between the Company and The Bank of New York Mellon Trust Company, N.A. (the current successor to Texas Commerce Bank National Association), as trustee (the “Indenture”). The terms of the Notes and the guarantees by WM Holdings will be set forth in an officers’ certificate of the Company delivered pursuant to the Indenture on the closing date.

Copies of the Underwriting Agreement and the Indenture, and the forms of the Officers’ Certificate and the guarantee agreement by WM Holdings are being filed as Exhibits 1.1, 4.1, 4.2, 4.3, 4.4, 4.8, 4.9 and 4.10, respectively, to this Form 8-K and are incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

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

INDEX TO EXHIBITS