Individual Taxpayer Identification Numbers (“I.T.I.N.’s”) are required by any individual who has a U.S tax filing obligation but is not eligible to be issued a Social Security Number. Without affixing an I.T.IN to a document filed with the I.R.S., it is extremely difficult for the document to be tracked by I.R.S. computers. When used on documents, an I.T.I.N. expires every five years. Otherwise, it expires after three consecutive years of non-use. In a series of F.A.Q.’s, Galia Antebi and Samantha Benenson address important questions. When do I.T.I.N.’s expire? Should you renew your I.T.I.N. if you are issued an S.S.N.? What are the implication of an expired I.T.I.N.? Can an I.T.I.N. be renewed before it is set to expire?