The problem with doing this (at least using Turbotax Online) is that even though you are telling Turbotax that the RMD was not taken in the proper tax year, Turbotax adds the amount of the RMD to your income (and to your federal and local taxes owed) in that tax year. This is incorrect because the income was not received in that tax year, so it should be added to your income in the year that you actually take the RMD. I haven't figured out a way around this using Turbotax, so I had to print out and mail in a paper Form 5329. Next year, both RMDs (the one missed in the previous tax year and the one for the current tax year) should show up on my 1099-R and be taxed as income received in the current tax year.