This guide details the methodology for the evaluation of tax expenditure in terms of personal income tax, capital gains tax and withholding tax, corporate income tax and minimum tax, custums duties, excise duties, value-added tax and registration duties. This method is based on the use of available tax data in the two administrations concerned by the management of these taxes : customs and tax administrations. This guide was produced by a team coordinated by Anne-Marie Geourjon and composed of Bertrand Laporte, Emilie Caldeira, Céline de Quatrebarbes and Yannick Bouterige. It draws on Ferdi's tax expenditure evaluation experiences in several developing countries.