Your down payment requirements with a co-signer depend on your situation - specifically, the type of loan you need and the type of home you plan to buy.  You may use a co-signer when buying a property that will be your primary residence - where you'll live year-round.  When adding a co-signer to a conventional mortgage, you can buy a 1-unit property, a single-family, townhome, or condominium with a minimum 5% down payment. For a 2-unit, you'll need at least a 15% down payment. And a 3-to-4-unit property requires a 20% down payment.  When using an FHA loan, you and your co-signer can buy a 1-unit with as little as 3.5% down. However, you'll need 25% for a down payment to buy a multi-unit, 2-to-4-unit property.  2 to 4 Unit Home | How to buy a multi-unit property The following chart shows the minimum down payment requirements...