Prepare An Illinois State Tax Amendment

If you need to change or amend an electronically or eFiled and accepted Illinois State Income Tax Return for the current tax you can do this online now. For previous Tax Year you need to complete Form IL-1040-X for the appropriate Tax Year. Form IL-1040-X is a Form used for the Tax Amendment. You can prepare a 2021 Illinois Tax Amendment on, however you cannot submit it electronically. In comparison, the IRS requires a different Form - Form 1040X - to amend an IRS return (do not use Form 1040 for an IRS Amendment). 

The IRS might have send you a notification to change your Federal Tax Return, or you might have discovered an error on a Return. If you or the IRS amended or changed one of your IRS Tax Return(s), the IRS will report this to the Illinois Tax Agency, thus you should file an Illinois Tax Amendment within one year.

File a 2021 Illinois Tax Amendment
eFile an IL Tax Amendment here. If you did not electronically file your IL return, you can prepare it here on
Only Option: You will need to complete, sign IL Form IL-1040-X for the appropriate Tax Year- Print, Mail the Form to IL Tax Department to:
Illinois Department of Revenue
P.O. Box 19047
Springfield, IL 62794-9047
IL Tax Amendment Form IL-1040-X
This Form can be used to file a: Tax Amendment, Change of Address.
Step 1: Select the Form IL-1040-X by Tax Year below. 
Step 2: Sign, Mail Form IL-1040-X to the address listed above
How to correct a rejected Tax Return
If your IL Tax Return was rejected by the IL Tax Agency - not - instructions on how to correct a rejected Illinois Tax Return.
Check Your IL Tax Amendment Status
1. Call the IL Department of Revenue at (800) 732-8866.
2. Contact the Illinois Department of Revenue
Illinois Refund Deadlines
A. Three years from the due date of the original tax year return, including valid filing extensions.
B. One year from the final determination of the amended federal return or federal change, whichever is later, provided that the allowable refund is not more than the decrease in Illinois tax attributable to the federal change or correction.
C. Two years from the payment of an assessment, provided the amended return raises issues relating only to the prior assessment and the refund does not exceed the amount of tax paid on the prior assessment.
D. Two years from the filing of an amended Illinois return resulting in the payment of additional tax, provided that the current amended return raises issues relating solely to the prior amended return and that the refund does not exceed the amount of the tax payment made as a result of the prior amended return.
Additional Illinois Tax Income Taxes Deadlines
Illinois Income Tax Penalties
Find out how Illinois Late Filing and Late Payment Penalties are calculated.
For IRS Tax and Late Filing Penalties we have an easy to use tool: The PENALTYucator.
File an IRS Tax Amendment by Tax Year
Instructions on how to prepare an IRS Tax Amendment on, however the IRS does not accept Tax Amendments electronically.