An Individual Taxpayer Identification Number (ITIN) is a tax processing number issued by the IRS upon receipt of Form W-7. The IRS issues ITINs to individuals required to have a U.S. taxpayer identification number who are not eligible for a Social Security Number (SSN) from the Social Security Administration. ITINs issue regardless of immigration status because both resident and nonresident aliens may have a U.S. filing or reporting requirement under the Internal Revenue Code. Individuals must have a filing requirement and file a valid federal income tax return to receive an ITIN, unless an exception applies. Each ITIN is a nine-digit number that always begins with the number nine.