If you itemize, you may be able to deduct the interest paid on money you borrowed to purchase a taxable investment.
If you receive rental income from the rental of a dwelling unit, there are certain rental expenses you may deduct on your tax return. These expenses may include mortgage interest, property tax, operating expenses, depreciation, and repairs.
Interest incurred for an investment in a "passive activity" generally doesn't qualify for the investment interest deduction. A passive activity is a business or trade in which you hold an ownership interest but in which you don't actually participate.