I received state and local tax refunds from 3 previous years. I itemized and paid AMT in each of the years. How can I determine if the refunds are taxable?

If all three of the following are true, your refund counts as taxable income:

• You itemized deductions last year, instead of taking the standard deduction.
• You claimed state and local income taxes (not general sales taxes).
• Claiming the deduction helped you increase your federal refund or lower your tax bill.

Even when your refund is taxable, it may not be the entire amount. It depends on how much the deduction affected your refund or tax bill. 

When you enter those state and local tax refunds received in 2017, TurboTax will determine if those refunds are taxable. 

I've added directions here to help you enter those tax refunds (only enter those received in 2017):

Enter Refund with 1099-G

https://ttlc.intuit.com/replies/4768356

Enter tax refund without Form 1099-G

https://ttlc.intuit.com/replies/5358269