Baxter International (BAX)

(Registrant’s telephone number, including area code)

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 is an accelerated filer (as defined in Rule 12b-2 of the Exchange Act).    Yes  x    No  ¨

The number of shares of the registrant’s Common Stock, par value $1.00 per share,

outstanding as of March 28, 2005 was 619,758,508 shares.

EXPLANATORY NOTE

Baxter International Inc. is filing this Form 10-Q/A Amendment No. 1 for the quarter ended June 30, 2004 to reflect the restatement of its consolidated financial statements for the quarters ended June 30, 2004 and 2003. The restatement arises from the controls surrounding the income tax accounts. Specifically, current income taxes payable balances were not reconciled to expected tax payments due, and the company did not adequately review the difference between the income tax basis and the financial reporting basis of assets and liabilities, and reconcile the difference to recorded deferred income tax assets and liabilities. Refer to Note 2A for a complete description and quantification of the restatement. Also, refer to Note 2 regarding the company’s previous restatement of its consolidated financial statements for 2001 through 2003 and the first quarter of 2004.

The information in this Form 10-Q/A Amendment No. 1 has not been updated from the original Form 10-Q except as required to reflect the effects of the restatement. This restatement includes changes to Part I, Items 1, 2 and 4. Items included in the original Form 10-Q that are not included herein are not amended and remain in effect as of the date of the original filing. Additionally, this Form 10-Q/A Amendment No. 1 does not purport to provide an update or a discussion of any other developments at the company subsequent to the original filing.

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PART I. FINANCIAL INFORMATION

(Registrant’s telephone number, including area code)

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 is an accelerated filer (as defined in Rule 12b-2 of the Exchange Act).    Yes  x    No  ¨

The number of shares of the registrant’s Common Stock, par value $1.00 per share,

outstanding as of March 28, 2005 was 619,758,508 shares.

EXPLANATORY NOTE

Baxter International Inc. is filing this Form 10-Q/A Amendment No. 1 for the quarter ended September 30, 2004 to reflect the restatement of its consolidated financial statements for the quarters ended September 30, 2004 and 2003. The restatement arises from the controls surrounding the income tax accounts. Specifically, current income taxes payable balances were not reconciled to expected tax payments due, and the company did not adequately review the difference between the income tax basis and the financial reporting basis of assets and liabilities, and reconcile the difference to recorded deferred income tax assets and liabilities. Refer to Note 1A for a complete description and quantification of the restatement.

The information in this Form 10-Q/A Amendment No. 1 has not been updated from the original Form 10-Q except as required to reflect the effects of the restatement. This restatement includes changes to Part I, Items 1, 2 and 4. Items included in the original Form 10-Q that are not included herein are not amended and remain in effect as of the date of the original filing. Additionally, this Form 10-Q/A Amendment No. 1 does not purport to provide an update or a discussion of any other developments at the company subsequent to the original filing.

2

PART I. FINANCIAL INFORMATION