Exactly 100 Vermont state representatives voted for the measure
Both houses in the US state of Vermont's legislature have voted to legalise same-sex marriage.
Vermont will become the fourth state to allow gay marriage, and the first to do so by a legislative vote and not a court ruling.
Republican Governor Jim Douglas vetoed the law when it originally passed.
This time, politicians in both of the state's legislative chambers voted for the measure with majorities big enough to block the governor's veto.
Vermont's Senate easily passed the proposal, with 23 votes to five, while the state's House of Representatives approved it by 100 votes to 49, the minimum needed to override the governor's veto.
As a result of the votes, same-sex marriage will become legal in Vermont on 1 September.
"It's been a very long battle. It's been almost 20 years to get to this point," said former Democratic State Representative Robert Dostis, who celebrated the vote at Vermont's legislature with his long-term partner Chuck Kletecka.
"I think finally, most people in Vermont understand that we're a couple like any other couple. We're as good and as bad as any other group of people."
In Massachusetts, Connecticut and Iowa, courts have ruled that bans on same-sex marriage are unconstitutional.
In California, the state legislature had voted to legalise gay marriage, although the measure was overturned in a referendum in November.