Gay rights activists Jose Maria Di Bello and Alex Freyre were married in Ushauaia, the capital of Argentina's Tierra del Fuego state, in a ceremony witnessed by sate and federal officials.
"My knees didn't stop shaking," Di Bello said. "We are the first gay couple in Latin America to marry."
The couple had previously tried to marry in the Argentine capital of Buenos Aires but were thwarted by city officials citing conflicting judicial rulings. Argentina's Constitution is silent on whether marriage must be between a man and a woman, effectively leaving the matter to state and city officials.
Tierra del Fuego Gov. Fabiana Rios said in a statement that gay marriage "is an important advance in human rights and social inclusion and we are very happy that this has happened in our state."
An official representing the federal government's antidiscrimination agency, Claudio Morgado, attended the wedding in the city of Ushauaia and called the occasion "historic."
Many in Argentina and throughout Latin America remain opposed to gay marriage, particularly the Roman Catholic Church.
But same-sex civil unions have been legalized in Uruguay, Buenos Aires, Mexico City and some states in Mexico and Brazil. Marriage generally carries more exclusive rights such as adopting children, inheriting wealth and enabling a partner to gain citizenship.
Di Bello said the city of Ushuaia initially declined to authorize the marriage but went ahead after the couple received backing from the state of Tierra del Fuego.
"We filed an administrative appeal to the government of Tierra del Fuego, which finally authorized the wedding.
A bill that would legalize gay marriage was introduced in Argentina's Congress in October but it has stalled without a vote.
Only seven countries in the world allow gay marriages: Canada, Spain, South Africa, Sweden, Norway, the Netherlands and Belgium. U.S. states that permit same-sex marriage are Iowa, Massachusetts, Vermont, Connecticut and New Hampshire.
Di Bello, 41, an executive at the Argentine Red Cross, met Freyre, 39, executive director of the Buenos Aires AIDS Foundation, at an HIV awareness conference. Both are HIV-positive.