The results of the 2009 Bundestag election and subsequent Land elections suggest that the German party system is changing fundamentally. A few facts suffice to corroborate this statement: Volatility has now reached levels that were last recorded in the 1950s; turnout in national elections has reached an all-time low; the two large parties have had unprecedentedly poor results in the Bundestag elections while all three smaller parties reached more than 10 percent. The article shows that German catch-all parties are about to lose their hold on the electorate and, as a result, can no longer rely on being the senior parties of government. The article analyses these changes systematically using a range of quantitative indicators covering the entire post-war period. It shows a seminal erosion of the forces which have stabilized the German party system in earlier decades and discusses the repercussions for the functioning of German party democracy.