An Individual Taxpayer Identification Number (ITIN) is issued by the IRS to individuals who are required to have a U.S. taxpayer identification number but who do not have, and are not eligible to obtain, a Social Security number (SSN) issued by the Social Security Administration (SSA). Such individuals include immigrants in the U.S. who are not yet able to obtain a valid SSN, as well as nonresident aliens who are listed on a U.S. tax return. This webpage describes the purpose of the ITIN, as well as how it can be obtained.