Veterans Health Care Funding Guarantee Act of 2003 - Requires the Secretary of the Treasury to: (1) make available to the Secretary of Veterans Affairs for programs, functions, and activities of the Veterans Health Administration for FY 2005 120 percent of the amount obligated during FY 2002; and (2) adjust the amount provided after FY 2005 based on the number of enrolled veterans and the number of others eligible for and provided care and the percentage increase in the Consumer Price Index.

Repeals provisions which: (1) prohibit the appropriation, obligation, or use of funds for any Department of Veterans Affairs major medical facility project or lease unless such funds have been specifically authorized by law; (2) require the Secretary to submit to specified congressional committees a prospectus of a proposed medical facility involving an expenditure of more than $4 million or facility lease with an average annual rental of more than $600,000; and (3) require the Secretary to give Congress notice before obligating an amount of funds for a major medical facility project that would cause the total amount obligated to exceed the amount specified in the law for that project by more than 10 percent, and when proposing that funds be used for a purpose other than the purpose for which such funds were appropriated.