Get your taxes done using TurboTax

Inherited IRA's can indeed have a basis.     You would need the last filed 8606 form for the inherited IRA to get the line 14 amount to enter in the 1099-R interview.

TurboTax ONLY supports 8606 forms for the taxpayer and spouse.    Inherited IRA basis is required by the tax law to be kept separate and that is not supported by TurboTax.   You would have to manually fill out a 8606 in the name of the deceased with you as benificuary and attach that to a mailed tax return - it cannot be e-filed.

Also see this TurboTax FAQ:

https://ttlc.intuit.com/community/accessing/help/where-do-i-find-form-8606/00/25713

We'll automatically generate and fill out Form 8606 (Nondeductible IRAs) if you reported any of these on your tax return:

• Nondeductible contributions made to a traditional IRA
• Distributions from a traditional, SEP or SIMPLE IRA that had nondeductible contributions (excluding rollovers, conversions, recharacterizations, qualified charitable distributions, one-time distribution to fund an HSA, or return of certain contributions)
• Conversions from a traditional, SEP, or SIMPLE IRA to a Roth IRA
• Distributions from a Roth IRA (other than rollovers, recharacterizations, or a return of certain contributions)

However, if any of these 3 situations apply to you:

1. You received a distribution from an inherited traditional IRA that had nondeductible contributions
2. You transferred an inherited plan account to a Roth IRA
3. You received a distribution from an inherited Roth IRA that was not a qualified distribution

then you'll have to download and print Form 8606, manually fill it out (instructions), and print and file your return, as you won't be able to e-file.