The Individual Taxpayer Identification Number (ITIN) is a nine-digit number that is used to identify certain individual taxpayers within the tax system. The ITIN is assigned directly by the IRS to eligible nonresident and resident taxpayers who do not have and do not qualify for a Social Security Number. The first ITIN was issued back in 1996 when the IRS replaced the temporary Internal Revenue Service Number (IRSN) with the ITIN as a mean to address accurate identification of international taxpayers with tax return filing or reporting requirements. Until recently, the number was personal and valid for life. Well, not anymore!