The 2003 Campeonato Nacional Apertura Copa Banco del Estado was the 73rd Chilean League top flight tournament, in which Cobreloa won its sixth league title after eight years.
Santiago Wanderers qualify to playoffs as best placed team despite having drawn with Unión San Felipe.
Colo-Colo and Huachipato qualified as best losers.
All sixteen first level teams took part in this tournament, plus -and only for this edition-, all sixteen second level teams took part as well.
One of the qualified teams to the Copa Sudamericana coming from this division, Provincial Osorno.