How to Fill Out Form IL-425: Illinois Identity Verification Steps

Illinois Form IL-425 is the identity verification form you send to the Illinois Department of Revenue (IDOR) when the department has asked you to prove you filed a particular IL-1040 and you no longer have the letter it sent you. Fill in the four steps, attach one photo ID and one document showing your name at the address on the return, and mail the packet to IDOR’s Anti-Fraud Unit within 60 days of the date printed on the letter.¹

When to Use Form IL-425

IDOR flags certain IL-1040 returns for identity verification and holds processing, including any refund, until the filer confirms the return is theirs. If you still have the verification letter, the faster route is MyTax.illinois.gov, where you can enter the Letter ID and upload documents without an account.¹

IL-425 is the paper alternative for people who lost the letter, never received it, or prefer to respond by mail. The form collects the same identifying information and tells IDOR which tax year is at issue so it can match your documents to the flagged return.²

How to Fill Out Form IL-425

Download the form from the IDOR website. A Spanish version, IL-425 Español, is also available. The form has four steps, and blank fields will slow processing.²

Step 1: Identify Yourself

Enter your full name, Social Security number, mailing address, daytime phone number, and email address. If you filed jointly, add your spouse’s name and Social Security number. Use the same address that appears on the IL-1040 in question.

Step 2: Return Information

Write in the tax year IDOR is asking about. If verification requests cover more than one year, complete a separate IL-425 for each. The form then asks whether you filed the return yourself, authorized someone else to file it, or did not file it at all. If a return was filed fraudulently in your name, check the box indicating you did not file and skip to Step 4. Otherwise, enter the refund amount shown on that year’s IL-1040, or zero if you didn’t claim a refund.²

Step 3: Attach Documents

Step 3 is where the two required copies go. The next section covers what qualifies.

Step 4: Additional Information

Use this space to explain anything unusual, such as reporting identity theft, filing on behalf of a minor, or handling a deceased taxpayer’s return.²

Documents to Attach

Include one document from each of the two categories below. Send copies, never originals.²

Category 1 is photo identification showing your full name. Any one of these works:

Illinois driver’s license, current or expired less than one year
Out-of-state driver’s license, current only
State identification card
Passport
Military identification
Other government-issued photo ID
Current U.S. high school, college, or university photo ID
Employee photo ID accompanied by a recent payroll stub

Category 2 is a document showing your full name and the complete address used on the return. Any one of these works:

Utility bill (gas, electric, cable, cell phone)
Bank or credit card statement
Payroll stub or W-2
Property tax bill
Signed rental agreement
College or university transcript
Insurance policy (vehicle, homeowners, renters, health, or life)
Birth certificate, if the taxpayer is a minor
Death certificate, if the taxpayer is deceased

Two situations call for extra ID. If the taxpayer is deceased, add a photo ID of the third-party designee handling the response. If the taxpayer is a minor without their own ID, use the parent’s or guardian’s identification instead.²

Where to Mail It

Send the form and document copies to:

Illinois Department of Revenue
Anti-Fraud Unit
PO Box 19049
Springfield, IL 62794-9049¹

If you happen to still have the original verification letter, include a copy so the Anti-Fraud Unit can match your submission to the case faster. Do not staple IL-425 to an IL-1040 or any other tax return. It’s a standalone submission.

If You Did Not File the Return

Getting a verification letter for a return you never filed points to identity theft. You can report this online without using IL-425. On MyTax.illinois.gov, scroll to the Identity Verification section, select the Identity Verification Code link, choose “No, I did not file this return and need to report identity theft,” enter your contact information, and submit.¹

To report it by mail on IL-425 instead, check the “did not file” box in Step 2, skip Step 3, and use Step 4 to describe what happened. Still attach your two identity documents so IDOR can confirm who you are.

Deadline, Penalty, and Late Responses

You have 60 days from the date printed on the verification letter to respond.¹ Until IDOR receives and reviews your documents, the return stays frozen, no refund is issued, and processing does not continue. Not providing the required information can also lead to a penalty.²

If the 60 days have already passed, you can still respond. IDOR’s instruction for late responders is the same: submit one document from each category, either online or by mailing IL-425 to the Anti-Fraud Unit at the address above.¹ The department doesn’t publish processing times once documents arrive, so expect some delay with mailed responses. You can check for updates by signing in to MyTax Illinois to view your account balance and any notices sent to you.³

1
Illinois Department of Revenue. Identity Verification Letters Information
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Illinois Department of Revenue. IL-425 Identity Verification Documents
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Illinois Department of Revenue. Letters and Notices for Individual Income Tax