The senate, which led by leftist doctor President Jose Mujica and has far more cattle than its 3.3 million people, last week approved a bill legalizing marriage between "two people of different or the same sex."
Now the lower house, which passed a different version of the bill in December, must vote again on the bill for it to become law.
Passage would make Uruguay the second in the region to approve gay marriage after Argentina, which did so in 2010. Same-sex marriage has been permitted in Mexico City since 2009.
Uruguay's Catholic Church appealed during Easter week for the defense of the institution of marriage, but only eight opposition senators voted against the bill while 23 voted in favor.
Over the past six years, Uruguay has legalized civil unions for homosexuals and the adoption of children by same sex couples and opened the military to gays.
The new law allowing same-sex marriage also includes other changes applying to all locals regardless of sexual orientation. The minimum age for legal marriage will increase to 16 for all instead of the current 12 for women and 14 for men.
Same-sex couples who adopt will be allowed to choose the order in which a child uses family names.