I missed 529 deductions on past two years of taxes

[rexroats]

Can I go back on my past years taxes to deduct 529 contributions in Illinois

[PaulaM]

Yes, you can amend your prior years state tax returns to correct the prior years return for the contributions. Form IL-1040X and instructions are included in the link below.

Illinois Revenue website

[plamonta]

Similar question:  Missed 529 deductions in 2017 but for Alabama. Can I do something about it to get my deductions?

[DaveF1006]

You can file an amended 2017 Alabama state return to receive credit for the 529 contribution deduction. 

1. Sign in at TurboTax.com with the user ID you used when you filed your 2019 return. 
2. Select Show next to Your tax returns & documents.
3. Select Download .tax fIle. You'll need this to amend your return.

• If you don't have access to your tax return, you'll need to pay for access before you can download your .tax file.

1. Once you've got your .tax file, select 2017, and then select Amend (change) 2017 return.
2. In the expanded instructions, select download TurboTax Desktop 2017.
3. Install the TurboTax 2017 software.

• Windows instructions
• Mac instructions

1. Now open your .tax file in the TurboTax 2017 software by choosing File and then Open Tax Return (Windows) or TurboTax and then Open Tax Return (Mac). Browse to the location of your tax file and select Open.
2. You're ready to amend your 2017 return. Follow these instructions.