2018–19 Liga Nacional de Básquet season

The 2018–19 Liga Nacional de Básquet season is the 35th season of the top professional basketball league in Argentina. The season started on 22 September 2017 with the Torneo Súper 20, which finished on 22 December 2018. The regular season began on 5 December 2018 and finished on 12 May 2019. Following the last season, the competition continues with all 20 teams being placed in a single group, playing a double round-robin, where the best 16 teams at the end of the season qualify for the championship playoffs, while the two teams with the worst record play in a best-of-five relegation series. Before the start of the regular season, the Torneo Súper 20 took place, which awarded two berths to the 2019 Liga Sudamericana de Básquetbol. Quilmes was relegated after losing the playoff series against Atenas.