Item 1.01 Entry into a Material Definitive Agreement

Pursuant to an Indenture dated as of May 21, 2007 (the "Indenture") between United States Steel Corporation (the "Corporation") and The Bank of New York, as trustee (the "Trustee"), a copy of which was filed as Exhibit 4.1 to the Corporation's Report on Form 8-K filed on May 22, 2007, the Corporation and the Trustee entered into a Third Supplemental Indenture dated as of May 4, 2009 (the "Supplemental Indenture"). The Supplemental Indenture provides for the issuance and sets forth the terms (such as the conversion features) of the Corporation's 4.00% Senior Convertible Notes due 2014 (the "Notes"). The Supplemental Indenture also contains covenants regarding limitations on liens and sale- leasebacks and the purchase of the Notes upon a change of control as well as other customary provisions.

A copy of the Supplemental Indenture is attached as Exhibit 4.1 to this Form 8-K.

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

On May 4, 2009, the Corporation consummated the issuance and sale of $862,500,000 principal amount of the Notes pursuant to the terms of the Indenture and the Supplemental Indenture. The material terms of the Notes are set forth in the Notes and in the Indenture and the Supplemental Indenture.

A specimen Note is attached as Exhibit 4.2 to this Form 8-K.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

4.1 Third Supplemental Indenture dated May 4, 2009 to Indenture dated as of May 21, 2007

4.2 4.00% Specimen Senior Convertible Note due 2014