Beginning Farmers and Ranchers Tax Incentive Act of 2003 - Amends the Internal Revenue Code to exclude from gross income: (1) 100 percent of the gain from the sale or exchange of qualified farm property to a first-time farmer who certifies that the use of such property shall be as a farm for farming purposes for not less than 10 years after such sale or exchange; (2) 50 percent of the gain from the sale or exchange of qualified farm property to any other person who certifies that the use of such property shall be as a farm for farming purposes for not less than 10 years after such sale or exchange; and (3) 25 percent of the gain from the sale or exchange of qualified farm property to any other person for any other use. Limits the amount of any of the above exclusions with respect to any taxable year to $500,000 on a joint return.