The Campeonato Argentino de Mayores is an annual rugby union competition in Argentina. Although it is usually treated as such, it is not strictly a provincial competition, as the 25 competing teams do not represent the 25 provinces of Argentina, but rather the unions that make up the Unión Argentina de Rugby (UAR). Some of these unions represent more than one province, for example Noreste represents the provinces of Chaco and Corrientes. Other unions may only represent part of an actual province, most notably the unions that make up the province of Buenos Aires and also the unions of Santa Fe and Rosario, both within the borders of the province of Santa Fe.
The competition is split into three divisions,:
Zona Campeonato which contains the 8 best unions,
Zona Ascenso, with the next best 8 teams divided in two pools, with the winner of them play a play-off with the lowest two of the higher level for promotion to the Zona Campeonato. The last two of the pools play a play-off. The loser is relegated to Estimulo
Zona Estímulo with 9 teams. The winner is promoted to Ascenso.
In the 2012 edition, at the ' Zona Campeonato, the national teams of Chile and Uruguay will participate, while the national teams of Brazil and Paraguay will play in the third level.