To amend the Internal Revenue Code of 1986 to allow a deduction for capital gains for middle income taxpayers.

Middle Income Tax Relief Act of 1997 - Amends the Internal Revenue Code to allow a capital gains deduction for individuals of 50 percent of the qualified gain for the taxable year. Limits such gain to $400,000 reduced by the aggregate amount of such gain taken into account for prior years. Makes such deduction unavailable to taxpayers with gross incomes in excess of $250,000. Requires property sold or exchanged for such gain to have been held in excess of three years.