Internal Revenue Service – IRS Love Machine 11 years ago Internal Revenue Service IRSU.S. Government agency that oversees collection and enforcement of taxes. Established in 1862 by President Lincoln, IRS operates under Department of the Treasury. Also oversees gift, corporate, estate and excise taxes.Recommended for you:9 Tax Tips for the New Business Owners Tanning Service TaxInternal MeasureInternal FinanceInternal Market