The 2009–10 Bundesliga was the 47th season of the Bundesliga, Germany's premier football league. The season commenced on 7 August 2009 with the traditional season opening match involving the defending champions VfL Wolfsburg and VfB Stuttgart. The last games were played on 8 May 2010. There was a winter break between 21 December 2009 and 14 January 2010, though the period was reduced from six to three weeks.
Karlsruher SC and Arminia Bielefeld were directly relegated at the end of the 2008–09 season after finishing in the bottom two places of the table. Karlsruhe ended a two-year stint in Germany's top flight, while Arminia were relegated for the sixth time since the introduction of the Bundesliga, a current record, after five years.
A further place in the league was decided through a two-legged play-off. FC Energie Cottbus as 16th-placed Bundesliga team had to face 1. FC Nuremberg, who finished third in 2. Bundesliga. Nuremberg won both matches by an aggregated score of 5–0 and thus earned their seventh promotion to the Bundesliga since its introduction, also a current record. Their opponents ended a second three-year top flight tenure and left the Bundesliga without a club from former East Germany for only the second time since East German teams were included before the 1991–92 season, with the other time being in 2005–06.
Rules for classification: . 1Since both finalists of the 2009–10 DFB-Pokal were qualified for the 2010-11 UEFA Champions League, the 6th-placed team will qualify for the 3rd qualifying round of the 2010–11 UEFA Europa League. (C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished: (Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.
16th-placed Bundesliga team 1. FC Nuremberg faced 3rd-placed 2. Bundesliga team FC Augsburg for a two-legged play-off. The winner on aggregate score after both matches earned a spot in the 2010–11 Bundesliga. Nuremberg was participating in their second playoff in a row after winning promotion at the expense of Energie Cottbus in the playoff at the end of the 2008–09 season. The matches took place on 13 and 16 May, with Nuremberg playing at home first. Nuremberg won 3 – 0 on aggregate, thus retaining their spot in the Bundesliga for the next season.