What can I do if I think someone has filed a tax return using my Social Security number? Answer: The IRS has many security measures in place to verify the accuracy of tax returns and the validity of Social Security numbers (SSNs) or individual taxpayer identification numbers (ITINs) submitted. If you receive a notice from the IRS that leads you to believe someone may have used your SSN (or ITIN) fraudulently, please notify the IRS immediately by responding to the contact at the number printed on the notice or letter. If you're an actual or potential victim of identity theft and would like the IRS to mark your account to identify any questionable activity, please complete Form 14039, Identity Theft Affidavit (in English PDF or Spanish PDF). See the "Instructions for Submitting this Form" in Form 14039, for information on submitting it online, by mail or fax. You may also contact the IRS for specialized assistance at 800-908-4490. These IRS employees are available to answer questions about identity theft and resolve any tax account issues that resulted from identity theft. Review Publication 5027, Identity Theft Information for Taxpayers (in English PDF and Spanish PDF) for more information. Additional Information: Identity theft central Taxes. Security. Together. We all have a role to play in protecting your data Report a tax scam or fraud Get an identity protection PIN (IP PIN) IdentityTheft.gov Subcategory: Reporting identity theftCategory: IRS procedures Back to Frequently Asked Questions