President Cristina Fernández de Kirchner strongly supported this passage.
“The bill has passed. It is law. The executive power will be notified,” the senate president said as the vote was displayed on an electronic board in the chamber.
Many GLBT citizens in the country applauded the vote.
"Nearly every political and social figure has spoken out in favor of marriage equality," said Maria Rachid, president of the Argentine Federation of Lesbians, Gays, Bisexuals and Transsexuals.
"And we hope that the senate reflects this and that Argentina, from today forward, is a more just country for all families," she told the Associated Press.
The law, which also allows same-sex couples to adopt, had met with fierce opposition from the Catholic Church and other religious groups.
Ines Frank, from a group called Argentine Families Argentina, said opposition was not discrimination "because the essence of a family is between two people of opposite sexes.”
Argentina's capital is widely considered to be among the most gay-friendly cities in Latin America. It was the first Latin American city to legalize same-sex unions.
Argentina becomes the first Latin American country to legalize gay marriage.