Same sex couples will be allowed to apply to marry in Uruguay from Monday, nearly four months after a bill was approved by the country’s Congress.
President Jose Mujica signed the legislation in May but it was only due to enter into effect 90 days later.
About half a dozen couples should apply for dates at civil registry offices in the coming days, activists say.
Following Argentina in 2010, Uruguay became the second South American nation to pass same-sex marriage legislation.
Across Latin America, the number of countries allowing gay unions or marriages is growing.
In Brazil, the council that oversees the country’s judiciary said offices could not deny the issue of civil union documents when gay couples wanted full marriage certificates.
However, the issue still requires a bill to be approved by the Congress.
In Colombia, a judge recently ordered a notary to sign a document which – while not being a marriage certificate – in effect gave a same-sex couple the same rights as heterosexual couples.
Last week, Colima became the latest Mexican state to allow civil unions among gay couples.
Mexico City and the southern state of Quintana Roo already allow gay marriages, while Coahuila allows same-sex civil unions.
In April, Congress in Uruguay approved the bill by more than two-thirds of the lower chamber, despite stark opposition from the Catholic Church.
The proposal had already been passed by the Senate by 23 votes to 8 a week earlier.
It allows same-sex couples to choose the order of the surnames of the children they adopt.
In recent years, Uruguay has moved to allow same-sex civil unions, adoption by gay couples, and to allow gay members of the armed forces.
Uruguay’s neighbour Argentina legalised gay marriage in 2010.