Federal elections were held in Germany on 27 September 2009 to elect the members of the 17th Bundestag.

The Christian Social Union in Bavaria is a Christian democratic and conservative political party in Germany. Having a regionalist identity, the CSU operates only in Bavaria while its larger counterpart, the Christian Democratic Union (CDU), operates in the other fifteen states of Germany. It differs from the CDU by being somewhat more conservative in social matters, following Catholic social teaching. The CSU is considered the de facto successor of the Weimar-era Catholic Bavarian People's Party.