Date Certain Tax Code Replacement Act

Establishes the National Commission on Tax Reform and Simplification to review: (1) the present structure and provisions of the Code; (2) whether the tax systems of other countries could provide more efficient and fair methods of funding government revenue requirements; (3) whether the income tax should be replaced with a tax imposed in a different manner or on a different base; and (4) whether the Code can be simplified, absent wholesale restructuring or replacement. Requires a Commission report to Congress on review results, with recommendations for Code reform and simplification. Terminates the Commission 90 days after such report.

Authorizes appropriations (with interim funding).

Declares that any new Federal tax system should be approved by Congress in its final form before July 4, 2005, and, if not, Congress should be required to vote to reauthorize the Code.