PLAIN LANGUAGE SUMMARY IRS Adoption Taxpayer Identification Numbers Recent tax law changes require a taxpayer to provide a child's taxpayer identification number (TIN) to claim certain tax benefits for the child. An individual's TIN is generally the individual's social security number (SSN). The Internal Revenue Service has published regulations to assign Adoption Taxpayer Identification Numbers (ATINs) to prospective adoptive parents who cannot obtain an SSN for a child placed with them for adoption. The parent will apply for an ATIN using a new tax form, Form W-7A. The ATIN may be used to claim a dependency exemption, dependent care credit, or child tax credit. The regulations are effective for income tax returns due (without regard to extensions) on or after April 15, 1998. The full text of the regulations is set forth in the Federal Register dated November 24, 1997.