The Maryland State Senate passed same-sex marriage by a 25-22 vote Thursday night.
The passage of the bill comes less than a week after the House of Delegates passed the identical bill.
All three senators who represent Howard County citizens voted for the historic bill that will allow gay and lesbian couples to marry.
Republican Allen Kittleman and Democrats Ed Kasemeyer and James Robey all cast "yes" votes.
The bill now goes to Gov. Martin O'Malley for his signature.
The law, which goes into effect January 1, 2013 is expected to face a referendum challenge and could end up on the November ballot along with the bill that grants in-state tuition rates to some children of illegal immigrants.