As a prospective adoptive parent in the process of adopting a US citizen or resident, you will need a taxpayer identifying number (TIN) to claim a dependency exemption and if eligible, a child tax credit for the child who is being adopted. If as the prospective adoptive parent you do not have and are unable to obtain the child's Social Security number (SSN), you should request an adoption taxpayer identification number (ATIN) or individual taxpayer identification number (ITIN).
An ATIN is available if an authorized placement agency placed the child, who is a US citizen or resident, in your household as a prospective adoptive parent for legal adoption. To obtain an ATIN, use Form W-7A (.pdf), Application for Taxpayer Identification Number for Pending US Adoptions. For more information, refer to the Form W-7A and to Adoption Taxpayer Identification Number therein.
If the child is not a US citizen or resident, and if the child qualifies as a dependent, a TIN is still required. To obtain an ITIN, use Form W-7 (.pdf), Application for IRS Individual Taxpayer Identification Number. For more information, refer to Individual Taxpayer Identification Number (ITIN).