In 2023 the IRS said I underpaid my 2021 taxes. I filed an amended return & paid the additional $2678 in Dec 2023. Can that be deducted and how (using TurboTax 2023)?

[DoninGA]

Federal taxes owed and paid for a prior tax year are not reported on a current year federal tax return.

[xmasbaby0]

No, you cannot deduct additional federal tax you paid on a federal tax return.  There is a handful of states in which you can enter the federal tax you paid:

-Alabama, Iowa. Missouri, Montana, and Oregon.  If you are filing in one of these states watch for the deduction when you prepare your state return.