You would need to go back and amend the returns for each year you missed the required minimum distribution. You can do this in TurboTax going back three years or so but before then you may have to get a tax preparer to help you. Although you can only go back three years to amend a return to receive a refund of taxes, you can go back as long as necessary to amend returns if you owe taxes. For practical purposes, the statute of limitations on collecting federal income tax is ten years, so you wouldn't have to go back beyond then.