Gay Californians can now apply for marriage licences
New York is set to recognize same-sex marriages performed in other parts of the United States.
State Governor David Paterson has given state agencies until 30 June to change rules to recognize gay marriages.
The news came hours after California said it would start issuing marriage licenses to gay couples from 17 June.
The move does not legalize same-sex marriage in New York, but it means many bureaucratic restrictions experienced by gay couples will be lifted.
These include issues concerning family health care plans, property inheritance, tax breaks and adoption rights.
New York's agencies will have to report back to the governor's counsel on how existing state benefits and services for gay couples would be reformed.
"This is a milestone in the fight for fairness in New York," said Donna Lieberman, executive director of the New York Civil Liberties Union.
"Couples in New York who have never known true security for their families will be officially entitled to treatment by our state government that respects their rights."
The New York ruling means that if a gay couple from the state opt to marry in California or a country where same-sex marriage is legal, when they returned home their union would carry the same rights as that of a heterosexual married couple.
Earlier this month, California's top court ruled that a state law banning marriage between same-sex couples was unconstitutional.
The ban had been approved by voters in 2000 but it was challenged by gay rights activists and the city of San Francisco.
In its ruling, the California Supreme Court said the "right to form a family relationship" applied to all Californians regardless of sexuality.
Gay activists and legal experts predicted that decision would re-invigorate the fight for same-sex marriage rights nationwide.