Prepare your federal return with the Single or Head of Household filing status. Your partner should do the same. The IRS doesn't recognize registered domestic partnerships or civil unions as marriages.
However, if you're residents in one of the handful of states that recognize RDP and/or civil unions, you can file your state return jointly.
Important: If you're in an RDP and a resident of California, Nevada, Washington, or Wisconsin state, you also have to account for community property rules.
Tip: If you plan to file a joint state return in a state that recognizes your partnership, we strongly recommend using TurboTax CD/Download software instead of TurboTax Online. It will save you time, money, and hassle.