a temporary tax identification number issued for a child born in the U

Adoption Taxpayer Identification Number – A number issued by the Internal Revenue Service as a temporary taxpayer identification number for the child in a domestic adoption where the adopting taxpayers do not have and/or are unable to obtain the child's Social Security number (SSN). The ATIN is used by the adopting taxpayers on their federal income tax return to identify the child while final domestic adoption is pending.