Previous In the 1997 season, 1. divisjon merged from two divisions consisting of 12 teams each, to only one with 14 teams. In the 2001 season, 1. divisjon expanded from 14 to 16 teams. Only two teams were relegated in the 2000 season. In 2009, the number of teams in
Eliteserien expanded from 14 to 16. Therefore, only one team was relegated to 1. divisjon, whilst three teams were promoted to Tippeligaen.
Current Since 2012 four teams, finishing 3rd to 6th, has qualified for promotion play-offs. In the 2017 season the relegation format was changed. The previous format where four teams were relegated was replaced with a format with two relegation spots and one relegation play-off spot. The league is contested by 16 teams. During the course of a season, each club plays the others twice, home and away, for a total of 30 games for each club, and a total of 240 games in a season. The season starts in April and lasts until early November. The top two teams will be promoted to
Eliteserien, while the teams placed from third to sixth place will play a promotion-playoff against each other to earn the right to play a two-legged game against the 14th-placed team in Eliteserien to win promotion. The bottom two teams will be relegated to the
2. divisjon known as PostNord-ligaen, and the team in 14th place will play a two-legged playoff against the play-off winner among the two-second-placed teams in 2. divisjon.
Changes in competition format ==Current members==