6-K

FORM 6-K

U.S. SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE

SECURITIES EXCHANGE ACT OF 1934

Dated March 3, 2011

Commission File Number 1-14878

GERDAU S.A.

(Exact Name as Specified in its Charter)

N/A

(Translation of Registrant’s Name)

Av. Farrapos 1811

Porto Alegre, Rio Grande do Sul - Brazil CEP 90220-005

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  x Form 40-F  o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes  o No  x

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b):  Not applicable.

SIGNATURES

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

Date:  March 3, 2011

GERDAU S.A.
By:	/s/ Osvaldo Burgos Schirmer
Name:	Osvaldo Burgos Schirmer
Title:	Chief Financial Officer

2

EXHIBIT INDEX

Exhibit	Description of Exhibit
99.1	Material Fact, March 3, 2011

3

EX-99.1

Exhibit 99.1

MATERIAL FACT

GERDAU S.A. (Bovespa: GGBR; NYSE: GGB; Latibex: XGGB), in accordance with CVM Instruction nº 358, dated January 3, 2002, announces that its current measured, indicated and inferred mineral resources total 2.9 billion tonnes of iron ore, up from the 1.8 billion tonnes announced previously. This increase is due to (i) the new assessments recently conducted of the volumes and iron content of the mineral resources; and (ii) the acquisition of additional areas of land.

In this context, and in view of the outlook for commodities in the international market, especially iron ore, the Board of Directors, in a meeting held on March 1, 2011, determined that the Management should conduct further studies to explore alternatives for monetizing part of these resources by evaluating various strategic options.

Once these studies are concluded, a new Material Fact will be disclosed to the market, although it is not possible to ensure when and if these actions will be carried out.

Rio de Janeiro, March 3, 2011

Osvaldo Burgos Schirmer

Executive Vice-President

Investor Relations Officer