When using the normal guided turbotax approach it requires you to select the guide question that ask you if you made IRA contributions, even though you may not have done so this year. Once you get through a couple of no answers you are asked if you made nondeductible contributions in prior years. If you have been with turbo tax a while it might find a cost basis from prior years. If not you may have to find this from a prior 8606 you had included in a prior year. As you know, it was painful the very first time you created a form 8606. You need to get turbotax to trigger a worksheet so you can enter the total yearend value of your IRA account(s). It then will calculate the fractional multiplier used to reduce this years IRA withdrawal taxable distributions (like RMD withdrawals for example). You will reduce this year's taxes a bit and have a new cost basis value ready for next year's return. Don't be surprised if it is a small reduction in taxes owed.
