You need to amend you tax return. Your distribution might or might not be taxable, but it has to be reported as income. Your 1099-R was sent not only to you, but also to the IRS and they will match their information with your filing.
If you used TurboTax Online, simply log in to your account and select “Amend a return that was filed and accepted.” If you used our CD/download product, sign back into your return and select “Amend a filed return.”
