This is highest football league in Argentina and is founded in 1931 year. It`s built by 26 football clubs, and is one of the toughest football championships in the world. Each team play one match against every other team in the league and teams are ranked in table according to points they won during the season. At the end of the season, the club with most points is champion of Argentina. Relegation of teams is calculated according last 3 years average points. Last four clubs with lowest average odds for last three years are relegated to lower Primera B Nacional. Clubs with most titles won is River Plate – 36 titles, followed by Boca Juniors -33 titles. Racing – 17 titles.