Amending My Return

Do not file another Form IL-1040 to make changes to a previously filed Form IL-1040. You must file Form IL-1040-X, Amended Individual Income Tax Return, if

you discover that you made an error on your Illinois return after it was filed, or
your federal return has been adjusted either by the Internal Revenue Service (IRS) or on a 1040X, Amended U.S. Individual Income Tax Return, you filed; the change affects your Illinois income, additions, subtractions, exemptions, or credits; and the change is final.

Note: If the federal change results in a refund, do not file Form IL-1040-X until you receive notification that your change has been accepted by the IRS.

For more information, see Form IL-1040-X and instructions.