The 1906 Argentine Primera División was the 15th season of top-flight football in Argentina. The 1906 championship was expanded to include 11 teams. The teams were split into two groups with each team playing the others in their group twice. The two group winners played in a championship decider.

The Club Atlético de San Isidro is an Argentine sports club based in the city of San Isidro in Greater Buenos Aires. Originally established as a football club, San Isidro has gained recognition for its rugby union team, holding a record of 33 Torneo de la URBA championships. The senior squad currently competes at Top 12, the top division of the Unión de Rugby de Buenos Aires league system.