UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

(Amendment No. 1)

(Mark One)

for the fiscal year ended December 31, 2009

OR

for the transition period from              to             

Commission file number: 1-13888

GRAFTECH INTERNATIONAL LTD.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (216) 676-2000

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  x    No  ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ¨    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer”, “non-accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Exchange Act Rule 12b-2).    Yes  ¨    No  x

The aggregate market value of our outstanding common stock held by non-affiliates, computed by reference to the closing price of our common stock on June 30, 2009, was approximately $ 1,352 million. On January 29, 2010, 120,557,499 shares of our common stock were outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

The information required under Part III is incorporated by reference from the GrafTech International Ltd. Proxy Statement for the Annual Meeting of Stockholders to be held on May 20, 2010, which will be filed on or about April 9, 2010.

GrafTech International Ltd. Form 10-K/A

Explanatory Note

GrafTech International Ltd. (“registrant,” “we,” or “our”) is filing this Form 10-K/A to include in its Annual Report on Form 10-K for the year ended December 31, 2009, the consolidated financial statements and related notes of Seadrift Coke, L.P. (“Seadrift”), pursuant to Rule 3-09 of Regulation S-X under the Securities Exchange Act of 1934, as amended. Seadrift, a privately-held limited partnership, is an unconsolidated investment in which we own 18.9% of the limited partnership equity interests. We account for our investment in Seadrift using the equity method of accounting.

Our equity in losses is based on Seadrift’s results of operations with a one-month lag adjusted for items we believe to be material intervening events: the amount to reduce certain inventories to LIFO cost of $2.3 million ($5.3 million in 2008), the write-off of construction in process for abandoned projects of $11.6 million, and the favorable fair value adjustments for an interest rate swap of $1.1 million. These items are subsequently reversed in recognizing our equity in Seadrift’s December results of operations. The following table shows the reconciliation of Seadrift’s net income (loss) for the twelve months ended December 31, 2009 and 2008 to that used by us to determine our equity in losses for the twelve and five months ended November 30, 2008 (dollars in millions):

We have amended Item 15(a)(1) of our Report on Form 10-K to include a reference to the required audited financial statements of Seadrift as of and for the years ended December 31, 2009 and 2008, and filed those financial statements as Exhibit 99.1.0 of this Form 10-K/A. Item 15 is the only Item of our Form 10-K being supplemented or amended by this Form 10-K/A.

This Form 10-K/A has not been updated for events or information subsequent to the date of filing of the original Form 10-K except in connection with the foregoing. Accordingly, this Form 10-K/A should be read in conjunction with our other filings made with the SEC subsequent to the filing of our Report on Form 10-K.

Part IV

See Index to Consolidated Financial Statements at page 56 of this Report.

Audited financial statements of Seadrift as of and for the years ended December 31, 2009 and 2008 filed pursuant to Rule 3-09 of Regulation S-X as Exhibit 99.1.0 to this Form 10-K/A.

None.

The exhibits listed on the following table have been filed with this Form 10-K/A.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

EXHIBIT INDEX