Tax Identification Code Tax Identification Code (CIF) was until 2008 the name and tax identification system used in Spain to legal persons or entities in general by Decree 2423/1975 regulates of 25 September. This Act is repealed with effect from 1 January 2008 by the Royal Decree 1065/2007, of July 27 that defines the use of tax identification number. The values of the letters are expanded EHA/451/2008 the Order of 20 February 2008 (BOE No. 49), by regulating the composition of the tax identification number of legal persons and entities without legal personality.