Primera B Nacional (usually called simply Nacional B, in English National B Division) is the second most important category of Argentine football organized by the Argentine Football Association.
It is played by teams from all over the country. Clubs from Buenos Airessurroundings, as well as some from Santa Fe province, are promoted from or relegated to the Primera B Metropolitana (Metropolitan B Division) while for teams from the other provinces the Torneo Argentino A (Argentine A Tournament) is the next level down. In the league system of Argentine football, Nacional B is the second-highest league, and from it the three best teams are automatically promoted to Primera División.
After the 1985/86 season, the Primera B Nacional became the second hierarchical football league in Argentina's professional football, after the First Division, and it is above the Torneo Argentino A and the Primera B or Primera B Metropolitana, the last one started to act as a third division for the teams directly affiliated to AFA.
The Primera B Nacional tournament had several formats during its history. Since the 2007/08 the competition format follows the usual double round-robin format. During the course of a season, which usually lasts from August to May, each club plays every other club twice, once at home and once away, for a total of 42 games. Teams receive three points for a win, one point for a draw, and no points for a loss. Teams are ranked by total points, with the highest-ranked club at the end of the season crowned champion. In the current format, the champion, the runner-up and the third placed team are automatically promoted to Primera División.