Five states, as well as the District of Columbia, now allow same-sex couples to file joint income tax returns.  Connecticut, Massachusetts and Vermont allowed for joint returns in previous years but 2007 is the first year it’s allowable in California, the District of Columbia and New Jersey.

However, the process can be a bit complicated.  Same-sex couples are not allowed to file joint federal returns.  Therefore, at a minimum, couples will need to file two federal forms in addition to the one state form.  Also, some states require couples to be registered as domestic partners before they can file jointly.

For more information, consult the tax department of your state -

California Franchise Tax Board

Connecticut Department of Services

District of Columbia Taxpayer Service Center

Massachusetts Department of Revenue

New Jersey Taxation

Vermont Department of Taxes