What to Do If Someone Claimed Your Dependent on Taxes

If someone else already claimed your dependent and your e-filed return was rejected, here is what to do if someone claimed your dependent on your taxes: print and mail a paper return claiming the dependent exactly as you intended, wait for the IRS to send Notice CP87A to both filers, and be ready to prove with third-party documents that the child lived with you and that you supported them. The IRS cannot resolve competing claims electronically, so paper filing is the only way to force a review.

File a Paper Return Claiming the Dependent

The rejection you received almost certainly carried a code like IND-507-01, which means the dependent’s Social Security Number already appeared on another accepted return.¹ The e-file system has no way to decide between two claims. It just blocks the second one, and no amount of retrying will get it through.

Print a complete Form 1040 with every schedule, claim the dependent as you originally intended, and calculate every credit you qualify for, including the Child Tax Credit and the Earned Income Tax Credit. Sign it, date it, and mail it to the IRS service center for your state. That single act starts the manual review that will eventually decide who was entitled to the claim.

Expect to wait. The IRS generally needs at least six weeks just to begin processing a mailed return, and that stretches during peak filing months.² If you were counting on the refund to cover something specific, adjust the plan now.

What the IRS Does After You File

Once your paper return is processed and the duplicate SSN is confirmed, the IRS mails Notice CP87A to both you and the other person. The notice identifies the overlapping Social Security Number and asks whoever filed incorrectly to submit an amended return.³

CP87A is not a bill and does not accuse either filer. It is a chance for the wrong party to back out voluntarily. If neither of you amends, the case escalates to an examination, and both sides will be asked to prove eligibility.

Do not ignore the notice. If you don’t respond and the IRS ends up disallowing your claim, you’ll owe back the credits plus interest at the federal underpayment rate, which was 7% in early 2026 and drops to 6% starting in April 2026.⁴

Documentation That Will Decide the Dispute

The IRS uses Form 886-H-DEP as its checklist during a dependent examination. Working from that checklist before you’re asked is the single most useful thing you can do.⁵ The evidence sorts into two piles: proof of where the dependent lived, and proof of who paid for them.

Residency

You need to show the child lived at your address for more than half the year. The IRS puts real weight on records from third parties it cannot dismiss as biased. School enrollment records showing your address, medical records listing your household, and daycare provider statements are strong. Lease agreements or mortgage documents naming the child as a household member help too.

The IRS specifically will not accept documents signed by someone related to you.⁵ A letter from your mother saying the child lived with you carries no weight. Stick with schools, doctors, government agencies, and places of worship producing statements on official letterhead with names, the shared address, and dates.

Support

If the examination turns on financial support, you’ll need to document that you paid more than half of the dependent’s total living expenses. The IRS counts food, housing, clothing, education, medical care, recreation, and transportation.⁶ For housing, the figure is the fair rental value of the shelter you provided, not your actual rent or mortgage payment.

Gather daycare receipts, medical bills, clothing purchases, and insurance premium statements. Child support agency records and any government benefits received by the dependent also enter the calculation. The IRS does not count the dependent’s own income and payroll taxes, life insurance premiums, or scholarships received by a student.⁶

If This Is About Custody

Most dependent disputes come from separated or divorced parents, and the rules here surprise people. Federal tax law defaults to the custodial parent, meaning the parent the child lived with for more nights during the year. A state court order saying “Father claims the child in even years” does not by itself override that.⁷ If both parents claim the child and the IRS applies its tie-breaker rules, the parent with more overnights wins; if the nights are equal, the parent with the higher adjusted gross income wins.

For a noncustodial parent to legitimately claim the child, the custodial parent has to sign Form 8332 releasing the claim, and the noncustodial parent must attach it to the return every year they use it.⁸ For divorce agreements finalized after 2008, nothing else substitutes for Form 8332. Older decrees from 1985 through 2008 may work if they explicitly grant the noncustodial parent the claim without conditions.⁷

Even a signed Form 8332 only transfers the Child Tax Credit and the credit for other dependents. It does not transfer the Earned Income Tax Credit or head-of-household filing status. Those stay with the custodial parent no matter what the agreement says.

If It Looks Like Identity Theft

When the person who claimed your dependent is a stranger rather than a relative or ex, treat it as identity theft. File Form 14039 (Identity Theft Affidavit) on behalf of the dependent, check the box indicating fraudulent use of a dependent’s SSN, fill in the dependent’s information, and note your relationship. Attach the completed form to the back of your paper return and mail them together, or submit Form 14039 online at irs.gov.⁹

One boundary worth knowing: the IRS does not treat it as identity theft when a parent or guardian claims a child, even if you think they had no right to. That is a dependent dispute, and it runs through the CP87A process described above, not the identity theft track.

If the IRS Sides Against You

If the examination ends against you, the IRS issues a Statutory Notice of Deficiency, often called a 90-day letter, proposing additional tax. You have exactly 90 days from the mailing date to file a petition with the U.S. Tax Court.¹⁰

The filing fee is $60 and can be waived for inability to pay. Attach a copy of the Notice of Deficiency with Social Security Numbers redacted, and explain plainly why you disagree. Do not attach returns or evidence at this stage. You’ll also file Form 4 (Statement of Taxpayer Identification Number) and Form 5 (Request for Place of Trial).¹⁰

The 90-day deadline is absolute. The Tax Court cannot extend it. Miss it and your only remaining route is to pay the tax first and then sue for a refund in federal district court or the Court of Federal Claims, which is a slower and more expensive fight.

Prevent It Next Year With an IP PIN

Once the dispute is resolved, get an Identity Protection PIN for your dependent so no one can file first next year. An IP PIN is a six-digit number the IRS assigns, and any return claiming that person has to include it or the return is rejected. Anyone with a Social Security Number can enroll.¹¹

A dependent 18 or older can request their own PIN through an IRS online account. For a child under 18, a parent submits Form 15227 online, and the IRS calls the number listed to verify identity before issuing the PIN. If neither route works, schedule an in-person appointment at a Taxpayer Assistance Center and bring two forms of identification for the dependent, such as a birth certificate and Social Security card.¹¹

1
Internal Revenue Service. Age, Name or SSN Rejects, Errors, Correction Procedures
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Internal Revenue Service. Refunds – How Long Should They Take
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Internal Revenue Service. Understanding Your CP87A Notice
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Internal Revenue Service. Internal Revenue Bulletin 2026-08
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Internal Revenue Service. Form 886-H-DEP – Supporting Documents for Dependents
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Internal Revenue Service. Publication 501 – Dependents, Standard Deduction, and Filing Information
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Internal Revenue Service. Publication 504 – Divorced or Separated Individuals
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Internal Revenue Service. Form 8332 – Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent
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Internal Revenue Service. Form 14039 – Identity Theft Affidavit
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United States Tax Court. Guidance for Petitioners – Starting a Case
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Internal Revenue Service. Frequently Asked Questions About the Identity Protection Personal Identification Number