If President Jose Mujica, who has signaled his support, signs the bill, Uruguay would become the second country in Latin America to legalize same-sex marriage and the 12th country in the world to do so, CNN reported Thursday.
The bill passed the lower house Wednesday, 71-21, while Uruguay's Senate approved the bill 23-8 last week.
In 2009, Uruguay became the first Latin American country to allow same-sex couples to adopt children. It also was among the first Latin American countries to recognize same-sex civil unions.
Argentina legalized same-sex marriages in 2010.
The Catholic Church opposed the measure in Uruguay, with church officials describing it as a blow to marriage and the family.
The president of Uruguay's Broad Front, a coalition of left-wing political parties backing the measure, said last week the bill is about human rights.
Lawmakers in France and Britain also are considering proposals to legalize same-sex marriage. In the United States, the Supreme Court is deliberating the matter.