2009–10 Rugby-Bundesliga

The 2009–10 Rugby-Bundesliga was the 39th edition of this competition and the 90th edition of the German rugby union championship. Ten teams played a home-and-away season with a finals round between the top four teams at the end. The bottom two teams are relegated. The season started on 29 August 2009 and finished with the championship final on 29 May 2010, interrupted by a winter break from early December to late March.

The competition's defending champion was SC 1880 Frankfurt, who won it in the previous two seasons. In the 2010 final, SC 1880 lost to Heidelberger RK, the previous seasons runners-up, which won its first championship since 1986 and its seventh overall. The final was drawn 22-all after regular time and was decided in extra time, where HRK scored 17 unanswered points to be crowned German champions of the men, already having won the 2010 women's final earlier that year. The 2010 final was contested by the two teams expected to do so at the start of the season, SC 1880 and HRK being the only two teams in Germany considered professional. The final was considered to have been of high niveau, with long-term German Bundestrainer Peter Ianusevici declaring it the best German championship final he had ever watched.

Below the Rugby-Bundesliga sat the 2nd Rugby-Bundesliga, which is divided into two divisions with ten teams each. With the RC Luxembourg, a team from Luxembourg, a non-German side competed in the league in 2009-10. The inclusion of this side in the 2009 promotion round to the 2nd Bundesliga had caused some debate in regard to its legality, as the club had not qualified to do so through the German league system and was not a member of any of the German regional rugby federations. However, RC Luxembourg's application was declared valid in regard to the German Rugby Federation's rules and regulations and the team finished second in the promotion round, earning a place in the 2nd Bundesliga for 2009-10.