You may not subtract anything that is not listed on Schedule M or Publication 101.
For example, you may not subtract:
- Unemployment compensation - Unemployment compensation included in your federal adjusted gross income, except railroad unemployment, is fully taxable to Illinois.
- Gambling losses - Illinois does not allow a deduction for gambling losses.
- Your federal itemized deductions from federal Form 1040 Schedule A, Itemized Deductions
- Any wages reported on your federal return - If you believe the wages reported on the Form W-2, Wage and Tax Statement, you received from your employer are incorrect, you must obtain a corrected Form W-2 or a statement from your employer, on company letterhead, stating that your Form W-2 was incorrect. We will not accept a letter from you or your tax preparer.
- Income received from Social Security benefits and retirement plans (including Illinois Teacher's Retirement) - Eligible retirement income should be subtracted on IL-1040, Line 5.
- Out-of-state income - However, if you are filing as a resident or a part-year resident, you may be allowed to take a credit against Illinois Income Tax for income tax you paid to another state. See the instructions for Form IL-1040, Line 15, and Schedule CR, Credit for Tax Paid to Other States.