History
The Unión de Rugby de Cuyo was founded on 22 September 1945, for clubs from the provinces of Mendoza and in western Argentina. The competition started in 1946 and has taken part every year since. San Juan clubs seceded in 1952, and founded the Unión Sanjuanina de Rugby, but still took part in the tournament. The last union to take part in the competition, Unión de Rugby de San Luis, was founded much later, in 1977. Traditionally, the Torneo del Oeste has been dominated by clubs from Mendoza. == Formula ==
Formula
The tournament, named "Regional de Cuyo Top 10" is contested by ten clubs competing in different levels, from the top division ("Primera") to lower levels. == List of champions ==