How many years must one claim that an inherited IRA is due to spousal death? Just the year after the death?

The answer depends on whether the surviving spouse has maintained the IRA as an inherited IRA in the name of the deceased spouse for the benefit of the surviving spouse or if the surviving spouse has chosen to treat the IRA as the surviving spouse's own.  While maintained as an inherited IRA, Forms 1099-R for distributions from the IRA will have code 4 in box 7 for a traditional IRA.  Once the surviving spouse rolls the money over to the surviving spouse's own IRA or chooses to treat the inherited IRA is the surviving spouse's own by having the IRA custodian re-title the IRA with the surviving spouse as owner or by trustee-to-trustee transferring the inherited IRA to an IRA with the surviving spouse as owner, the IRA will no longer be an inherited IRA.  Forms 1099-R reporting distributions from an IRA owned by the surviving spouse will have code 1, 2 or 7 in box 7 for a traditional IRA.