Declining party membership in Denmark is analysed in light of the general development of political participation in the 1970s and 1980s. It is demonstrated that the decline in party membership had nothing to do with a general decline in participation. The decline is rather the result of three different processes: (1) the declining number of farmers, (2) the weakening of the organization of the workers, and (3) the political mobilization of the new middle class and women. It is argued, therefore, that the causes of the decline are primarily demographic and socio‐economic. It is furthermore argued that the declining membership threatens the traditional mobilizing and socializing functions of the parties and thereby may increase political inequality in the Danish societ