The 2009–10 Season of BAI Basket (32nd edition) ran from November 13, 2009 to June 15, 2010, with 12 teams playing in three different stages: in stage one (regular season) teams played a double round robin system.

In stage two, the six best teams played a single round robin tournament in serie A and the last six did the same for the consolation group, serie B.

Finally, in stage three (final four) the best four teams from serie A played in a round robin at four rounds for the title.

Regular Season Standings As the regular season winner, Primeiro de Agosto is awarded a bonus point for the group stage.

Serie A As the group stage winner, Primeiro de Agosto is awarded a bonus point for the final four.