SECURITIES AND EXCHANGE COMMISSION

FORM 8-A/A

Amendment No. 1

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
PURSUANT TO SECTION 12(b) OR (g) OF THE
SECURITIES EXCHANGE ACT OF 1934

PEABODY ENERGY CORPORATION

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

If this form relates to the registration of a class of securities pursuant to Section 12(b) of the Exchange Act and is effective pursuant to General Instruction A.(c), please check the following box:    x

If this form relates to the registration of a class of securities pursuant to Section 12(g) of the Exchange Act and is effective pursuant to General Instruction A.(d), please check the following box:    o

Securities Act registration statement file number to which this form relates: N/A

Securities to be registered pursuant to Section 12(g) of the Act: None

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     The undersigned Registrant hereby amends its Registration Statement on Form 8-A filed with the Securities and Exchange Commission on July 24, 2002 with respect to its common stock purchase rights as set forth herein.

Item 1. Description of Registrant’s Securities to be Registered.

     On March 2, 2005, Peabody Energy Corporation (the “Company”) announced that its Board of Directors had declared a two-for-one stock split on all shares of its common stock, $0.01 par value, of the Company (the “Common Stock”), whereby all stockholders of record at the close of business on March 16, 2005 are to receive one additional share of Common Stock for every share held on that date. The additional shares will be distributed to stockholders in the form of a stock dividend on March 30, 2005.

     In connection with the stock dividend, the Board of Directors of the Company also made required adjustments to the preferred share purchase rights (the “Rights”) issued in connection with each outstanding share of Common Stock and which will be issued in connection with each share of Common Stock distributed pursuant to the stock dividend. To account for the stock dividend, the number of shares of Series A Junior Participating Preferred Stock, par value $0.01 per share (the “Preferred Shares”) purchasable upon the exercise of one Right has been adjusted from one one-hundredth of a Preferred Share to one half of one one-hundredth of a Preferred Share.

     The adjustments were made in accordance with the provisions of the Rights Agreement dated as of July 24, 2002 between the Company and EquiServe Trust Company, N.A., as Rights Agent, which Rights Agreement is attached as an exhibit to the Company’s Form 8-A filed with the Securities and Exchange Commission on July 24, 2002. A copy of the Certificate of Adjustment delivered to the Rights Agent pursuant to the Rights Agreement, which sets forth such required adjustment, is attached hereto as Exhibit 4.2 and is incorporated herein by reference.

Item 2. Exhibits.

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     Pursuant to the requirement of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this amendment to be signed on its behalf by the undersigned, thereto duly authorized.

Date: March 29, 2005

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