The 2008–09 Argentine Primera B Nacional was the 23rd season of second division professional of football in Argentina.
A total of 20 teams competed; the champion and runner-up were promoted to Argentine Primera División.
Note: Clubs with indirect affiliation with AFA are relegated to the Torneo Argentino A, while clubs directly affiliated face relegation to Primera B Metropolitana.
The bottom two teams of this table face relegation regardless of their affiliation status.
Apart from them, the bottom teams of each affiliation face promotion/relegation playoffs against Torneo Argentino A and Primera B Metropolitana's "Reducido" (reduced tournaments) champions.