Assuming that it is a Traditional IRA, yes, it is taxable as ordinary income unless there was some after-tax "basis" in the IRA. You would need the fathers past tax returns to see if he ever filed a 8606 form if he took a distribution or made a non-deductible contribution.
You should receive a 1099-R with a code 4 in box 7 for an inherited Traditional IRA.
(If a Roth IRA 1099-R with a code T in box 7 then it would not be taxable since Roth's are after-tax money)
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
