An IRS adoption taxpayer identification number, or ATIN, is a temporary taxpayer identifying number assigned by the Internal Revenue Service to a child, other than an alien individual as defined in section 301.6109-1(d)(3)(i), who has been placed by an authorized placement agency in the household of a prospective adoptive parent for legal adoption (26 CFR 301.6109-3(a)(1)). It exists to fill the gap between placement and a social security number, and it stops being usable once that number arrives.
Temporary is the operative word in the definition, and it is the part that gets missed. The number has an expiry, it has an eligibility test with four conditions, and it does not stand in for a social security number everywhere on the return.
What the Regulation Actually Says
The number is assigned to the child upon application for use in connection with filing requirements under the Internal Revenue Code and the regulations thereunder. When an adoption becomes final, the adoptive parent must apply for a social security number for the child, and after the social security number is assigned, that number, rather than the ATIN, must be used as the child’s taxpayer identification number on all returns, statements, or other documents required under the Internal Revenue Code and the regulations thereunder (26 CFR 301.6109-3(a)(1)).
The expiry is automatic and the extension is not. An ATIN automatically expires two years after the number is assigned, however, upon request, the IRS may grant an extension if the IRS determines the extension is warranted (26 CFR 301.6109-3(a)(2)). Nothing in that sentence promises the extension.
Three terms carry defined meanings for purposes of the section. Authorized placement agency has the same meaning as in section 1.152-2(c) of the chapter. Prospective adoptive child, or child, means a child who has not been adopted, but who has been placed in the household of a prospective adoptive parent for legal adoption by an authorized placement agency. Prospective adoptive parent, or parent, means an individual in whose household a prospective adoptive child is placed by an authorized placement agency for legal adoption (26 CFR 301.6109-3(b)).
Who May Apply, and the Four Conditions
A prospective adoptive parent may apply for an ATIN for a child if four things hold, and the regulation joins them conjunctively. The prospective adoptive parent is eligible to claim a personal exemption under section 151 with respect to the child. An authorized placement agency places the child with the prospective adoptive parent for legal adoption. The Social Security Administration will not process an application for an SSN by the prospective adoptive parent on behalf of the child, for example because the adoption is not final. And the prospective adoptive parent has used all reasonable means to obtain the child’s assigned social security number, if any, but has been unsuccessful in obtaining this number, for example because the biological parent who obtained the number is not legally required to disclose the number to the prospective adoptive parent (26 CFR 301.6109-3(c)(1)).
The first of those four is worth reading twice, because the regulation and the IRS’s current guidance describe it differently. The regulation frames the condition as eligibility to claim a personal exemption under section 151. The IRS’s own guidance frames the same condition as “You are eligible to claim the child as a dependent on your tax return” (IRS, Adoption Taxpayer Identification Number (ATIN)). The regulation’s provisions apply to income tax returns due, without regard to extension, on or after April 15, 1998 (26 CFR 301.6109-3(d)), and its source note names a single Treasury Decision with no later amendment. The two wordings are recorded here as they read, without a claim about which one controls.
The IRS’s list adds a limb the regulation does not spell out, and it is the one that decides foreign cases. The adoption is a domestic adoption, or the adoption is a foreign adoption and the child has a permanent resident alien card or certificate of citizenship (IRS, Adoption Taxpayer Identification Number (ATIN)). A foreign adoption without one of those two documents does not qualify.
How the Application Runs
If the requirements are satisfied, the prospective adoptive parent may apply for an ATIN for a child on Form W-7A, Application for Taxpayer Identification Number for Pending Adoptions, or such other form as may be prescribed by the IRS. The application must include the information required by the form and accompanying instructions, including the name and address of each prospective adoptive parent and the child’s name and date of birth, and such documentary evidence as the IRS may prescribe to establish that a child was placed in the prospective adoptive parent’s household by an authorized placement agency for legal adoption (26 CFR 301.6109-3(c)(2)).
The same paragraph gives examples of acceptable documentary evidence: a copy of a placement agreement entered into between the prospective adoptive parent and an authorized placement agency, an affidavit or letter signed by the adoption attorney or government official who placed the child for legal adoption pursuant to state law, a document authorizing the release of a newborn child from a hospital to a prospective adoptive parent for adoption, and a court document ordering or approving the placement of a child for adoption (26 CFR 301.6109-3(c)(2)).
Timing is the practical constraint. The IRS says to apply as soon as the qualifying conditions are met, but at least 8 weeks before the due date of the individual federal income tax return, and that it will generally take 4 to 8 weeks to get an ATIN once the IRS receives a completed Form W-7A (IRS, Adoption Taxpayer Identification Number (ATIN)). Copies rather than originals go in, because the IRS will not return any submitted documentation (IRS, Adoption Taxpayer Identification Number (ATIN)).
The Deactivation Clock, and the Notice That Warns About It
As soon as the adoption becomes final, the adopting parents should obtain an SSN for the child and notify the IRS of the new SSN, and when the IRS is notified of a new SSN for the adopted child it will deactivate the ATIN. If the adopting parents do not notify the IRS within two years, the ATIN will be automatically deactivated (IRS, Adoption Taxpayer Identification Number (ATIN)).
There is a warning shot before that happens. A reminder notice will be sent eighteen months after the taxpayer receives the ATIN, informing the adopting parents that the ATIN will expire in 6 months (IRS, Adoption Taxpayer Identification Number (ATIN)). Where the adoption is not finalized before the ATIN expires, an extension may be applied for, and the eighteen month reminder notice explains what has to be done to apply (IRS, Adoption Taxpayer Identification Number (ATIN)).
What an ATIN Does Not Do
This is where a return goes wrong. An ATIN is a taxpayer identification number, and a TIN may be an ATIN, an ITIN, or an SSN (IRS, Instructions for Schedule 8812 (Form 1040) (2025)). Being a TIN is not the same as being an SSN, and several credits are written against the narrower term.
Not the earned income credit. The IRS answers it flatly: you can only use an SSN to claim the Earned Income Tax Credit (IRS, Adoption Taxpayer Identification Number (ATIN)).
Not the child tax credit or the additional child tax credit, for tax year 2025. If you have a qualifying child who does not have a valid SSN, you can’t use the child to claim the CTC or ACTC on either your original or an amended 2025 return, and for those credits a valid SSN is one that is valid for employment and that is issued by the Social Security Administration before the due date of the 2025 return including extensions (IRS, Instructions for Schedule 8812 (Form 1040) (2025)).
But it can support the credit for other dependents. If your qualifying child does not have a valid SSN, but has another type of taxpayer identification number issued on or before the due date of your 2025 return including extensions, you may be able to claim the ODC for that child, and a dependent who does not have an SSN, ITIN, or ATIN issued by that date cannot be used to claim the ODC at all (IRS, Instructions for Schedule 8812 (Form 1040) (2025)). The four conditions that credit runs on are set out in credit for other dependents.
And the child care credit is on the IRS’s own list of reasons to get one. If you are in the process of adopting a child and are able to claim the child as your dependent or are able to claim a child care credit, you may need an ATIN for your adoptive child (IRS, Adoption Taxpayer Identification Number (ATIN)).
Common Questions
No, and each definition excludes the other’s population. The term IRS individual taxpayer identification number means a taxpayer identifying number issued to an alien individual by the Internal Revenue Service, upon application, for use in connection with filing requirements under this title, and for purposes of that section the term alien individual means an individual who is not a citizen or national of the United States (26 CFR 301.6109-1(d)(3)(i)). The ATIN definition excludes exactly that class, because it is assigned to a child other than an alien individual as defined in section 301.6109-1(d)(3)(i) (26 CFR 301.6109-3(a)(1)). The two still sit alongside the SSN in one class on Schedule 8812, where a TIN may be an ATIN, an ITIN, or an SSN (IRS, Instructions for Schedule 8812 (Form 1040) (2025)). A business identifier is a different animal again, covered in employer identification number.
It stops being the right number. The adoptive parent must apply for a social security number for the child, and after the social security number is assigned, that number rather than the ATIN must be used on all returns, statements, or other documents required under the Internal Revenue Code and the regulations thereunder (26 CFR 301.6109-3(a)(1)). Notifying the IRS is what triggers deactivation (IRS, Adoption Taxpayer Identification Number (ATIN)).
Yes, on request and at the IRS’s judgment. Upon request, the IRS may grant an extension if the IRS determines the extension is warranted (26 CFR 301.6109-3(a)(2)). The route runs through Form 15100, the ATIN extension request, which the IRS includes in its ATIN notices (IRS, Adoption Taxpayer Identification Number (ATIN)).
At two points, and the second is the one that bites. At preparation, the number has to exist by the return’s due date for the dependent-based credits to survive. At the following year’s rollover, the prior year’s ATIN gets carried forward into a return where the adoption has since finalized, so the return goes out with a deactivated number on a dependent line. Neither problem is visible in the numbers. Both are visible in the client’s file.
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