If the estate was large enough to have paid estate taxes, there may be a deduction for income in respect of a decedent. Here's a snippet that explains how it works:
An overlooked deduction.
Most taxpayers and even many tax advisers are unaware of the deduction for 'income in respect of a decedent. But many people who inherit a substantial IRA are eligible for this deduction, which essentially is a deduction for the estate taxes that were paid on the IRA. The deduction is best explained with an example.
Suppose someone left a large estate with an IRA. The estate tax accountant computes that the IRA was responsible for 36.7% of the estate tax paid, and that the IRA's share of the estate tax was $175,000. When the beneficiary takes distributions from the IRA, a miscellaneous itemized deduction (not subject to the 2% floor) of 36.7% of each distribution is allowed. This continues until the beneficiary has deducted a total of $175,000 over the years.
The estate tax accountant should determine the data for the deduction. Details can be found in the IRS Publication 559, Survivors, Executors, and Administrators available free on the IRS web site, www.irs.gov.