Yes. Live in one unit of a two-unit property and the rent from the other unit can count toward your qualifying income. That extra income is one of the big reasons a duplex can pencil when a single-family home at the same price wouldn't. Just don't budget on the full rent. For a unit you're newly renting out, lenders work from the appraiser's market-rent opinion (the rent schedule on Form 1007 or 1025) plus any lease, and they credit 75% of the gross rent rather than 100%. Fannie Mae uses gross monthly rent times 75%, with the 25% holdback covering vacancy and maintenance; FHA applies a 75% factor to the lesser of the appraiser's market rent or the lease. Owning a rental comes with management, repairs, and empty months, and the haircut prices that in. So if the back unit would rent for a given amount, count on roughly three-quarters of it showing up as usable income on your application. The exact documentation depends on your loan program and whether the unit is already leased, so confirm the specifics for your program. The core answer stands: the back-unit rent helps you qualify, at about 75 cents on the dollar.