UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

(Amendment No.      )

Fresenius Medical Care AG

(Name of Subject Company (issuer))

Fresenius Medical Care AG (issuer)

Fresenius Medical Care AG & Co KGaA (issuer)

(Names of Filing Persons (identifying status as offeror, issuer or other person))

Preference Shares without par value

(Title of Class of Securities)

358029 20 5

(CUSIP Number of Class of Securities)

(Name, address, and telephone numbers of person authorized

to receive notices and communications on behalf of filing persons)

Calculation of Filing Fee

*Set forth the amount on which the filing fee is calculated and state how it was determined.

     Amount Previously Paid: $73,478.87 on October 7, 2005; $3,775.05 on December 23, 2005

     Form or Registration No.: 333-128899

     Filing Parties: Fresenius Medical Care AG; Fresenius Medical Care KGaA

     Date Filed: October 7, 2005 and December 23, 2005

     Preliminary Note: This Schedule TO relates to the offer (the “Conversion Offer”) to be made by Fresenius Medical Care AG (“FMC AG”) to U.S. holders of its non-voting preference shares (including preference shares represented by American Depositary Shares) to convert their shares into ordinary shares. Upon completion of the Conversion Offer and registration by the Commercial Register in Hof an der Saale, Germany, of the conversion of FMC AG’s preference shares into ordinary shares, FMC AG will undergo a transformation of legal form under German law from a German stock corporation into a German partnership limited by shares, to be called Fresenius Medical Care AG & Co. KGaA (“FMC KGaA”). FMC AG and FMC KGaA will make the Conversion Offer upon effectiveness of the registration statement on Form F-4 filed October 7, 2005 (Registration No. 333-128899) and amended by Amendment No. 1 thereto on November 17, 2005 and Amendment No. 2 thereto filed December 23, 2005, as the same may be amended. The information required by Schedule TO is incorporated by reference from the preliminary prospectus dated December 23, 2005 included in Amendment No. 2 to the registration statement (the “Prospectus”), including the periodic reports of FMC AG incorporated into the Prospectus, as more fully set forth below. Paragraph numbers referred to in each Item below refer to the paragraph numbers of the provisions of Regulation M-A referenced in such Items.

      Not applicable. Information will be disclosed to security holders pursuant to a prospectus meeting the requirements of Rule 421 under the Securities Act of 1933, as amended.

      (a) Incorporated by reference to the information set forth under the caption “Summary — The Company” in the Prospectus.

      (b) Incorporated by reference to the information set forth in the Prospectus under the caption “Description of the Shares of Fresenius Medical Care AG & Co. KGaA.”

      (c) Incorporated by reference to the information set forth in Item 9 in the amended Annual Report on Form 20-F/A of FMC AG for the year ended December 31. 2004 (the “FMC AG 2004 20-F/A”).

      The filing person is the subject company. The additional information required by Instruction C to Schedule TO is incorporated by reference to the information set forth in Items 6A and 7A in the FMC AG 2004 20-F/A. The business address and telephone number of each of the persons identified in such Items is c/o Fresenius Medical Care AG, Else-Kröner Strasse 1, 61352 Bad Homburg v.d.H., Germany.

      (a) Incorporated by reference to the information set forth under the caption “The U.S. Offer” in the Prospectus.

      (b) There are no arrangements for the purchase of any preference shares from any officer, director or affiliate of FMC AG. Such persons may participate in the Conversion Offer on the same terms as other holders of Preference Shares.

      (e) Incorporated by reference to the information set forth under the caption “Description of the Proposed Pooling Arrangements” in the Prospectus.

      (a) Incorporated by reference to the information in the Prospectus set forth under the caption “The Conversion and Transformation; Effects.”

      (b) Not applicable

      (c) Incorporated by reference to the information in the Prospectus set forth under the caption “The Conversion and Transformation; Effects.”

      (a) Not applicable

      (b) Not applicable

      (c) Incorporated by reference to the information in the Prospectus set forth under the caption “The Conversion and Transformation; Effects — Accounting Treatment — Transformation of Legal Form.”

      (a) Incorporated by reference to the information set forth in the Prospectus under the caption “Interest of Certain Persons in the Conversion and Transformation — Interest of Fresenius AG” and in Item 7E of the FMC AG 2004 20-F/A.

      (b) Neither FMC AG nor FMC KGaA has effected any transactions in the preference shares during the 60 days preceding the filing of this Schedule TO other than, in the case of FMC AG, issuance of preference shares upon the exercise of employee stock options. The information in the Prospectus under the caption “Interest of Certain Persons in the Conversion and Transformation: Recent Transactions in our Preference Shares” is incorporated herein by reference.

      (a) Incorporated by reference to the information set forth in the Prospectus under the caption “The U.S. Offer — Fees and Expenses”

      (a) Incorporated by reference to the information set forth in Item 18 of the FMC AG 2004 20-F/A and Part I, Item 1 of FMC AG’s Report on Form 6-K furnished to the SEC on November 3, 2005.

      (b) Not applicable.

      (c) Incorporated by reference to the information set forth in the Prospectus under the caption “Summary — Summary Consolidated Financial Information.”

      (a)(1) Incorporated by reference to the information set forth in the Prospectus under the caption “Interest of Certain Persons in the Conversion and Transformation.”

      (a)(2) Incorporated by reference to the information set forth in the Prospectus under the captions “The U.S. Offer — Conditions to the U.S. Offer” and “Stock Exchange Listing and Trading.”

      (a)(3) Not Applicable

      (a)(4) Not Applicable

      (a)(5) Incorporated by reference to the information set forth in the Prospectus under the caption “The Conversion and Transformation; Effects — Settlement of the Proceedings to Set Aside the Resolutions of the Extraordinary General Meeting of August 30, 2005.”

      (a)(1) Form of letter of transmittal (incorporated by reference to Exhibit 99.1 filed with Amendment No. 1 to the registration statement on Form F-4 of FMC AG and FMC KGaA (Registration No. 333-128899 filed November 17, 2005.)

      (a)(4) Preliminary prospectus dated December 23, 2005 (incorporated by reference to the prospectus contained in Amendment No. 2 to the registration statement on Form F-4 of FMC AG and FMC KGaA (Registration no. 333-128899) filed December 23, 2005).

      (b) Not applicable

      (d) Form of Pooling Agreement to be entered into among Fresenius AG, Fresenius Medical Care AG, Fresenius Medical Care Management AG (for itself and as general partner of Fresenius Medical Care AG & Co. KGaA), and the independent directors of Fresenius Medical Care AG & Co. KGaA. (Incorporated by reference to Exhibit 4.3 to Amendment No. 2 to the Registration Statement on Form F-4 of Fresenius Medical Care AG, Registration No. 333-124759, filed July 1, 2005).

      (g) Not applicable

      (h)(1)Tax Opinion of Nörr Stiefenhofer Lutz incorporated by reference to Exhibit 8.1 to Amendment No. 1 to the Registration Statement on Form F-4 (Registration No. 128899) filed November 17, 2005.

      (h)(2)Tax Opinion of O’Melveny & Myers LLP incorporated by reference to Exhibit 8.2 to Amendment No. 1 to the Registration Statement on Form F-4 (Registration No. 128899) filed November 17, 2005.

      Not Applicable

SIGNATURES

      After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.