The government is issuing the regulations needed to allow gay couples married in states that recognize same-sex marriages to file joint federal tax returns.
Treasury Secretary Jacob Lew says the new rules will provide "clear, coherent tax filing guidance for all legally married same-sex couples nationwide."
Lew said the regulations also make clear that legally married same-sex couples will be able to move freely throughout the country and their federal tax filing status will not change.
The new rules implement the tax aspects of the Supreme Court's ruling in June which invalidated a section of the 1996 Defense of Marriage Act.
The new regulations from Treasury and the Internal Revenue Service implement the court's decision on how legally married same-sex couples should be treated for federal tax purposes.