Research on political party members started on a grand scale at the beginning of the 1990s and it has gone in three main directions: (1) members and activists as a resource for the parties; (2) members as constituting “the party on the ground”; and (3) political participation of the members (van Haute, Paulis & Sierens 2017). In this article we are drawing from all three traditions of the research. The paper is based on empirical investigation from the project “Political Parties and their Social Environment. An Analysis of the Organization and Communication Activities of Polish Political Parties”, in which in-depth interviews with the parties’ leaders and parliamentarians were conducted and questionnaires were collected from the grassroots members and activists. To structure our research we put forward the following theses: (1) The parties’ elites declaratively appreciate the role of rank-and-file members in the organizations, but in practice rarely undertake activities to encourage people to join the parties or to engage the members they already have in party work. (2) The grassroots members would like to have more influence on party decisions. (3) The factor that is more important in differentiating the parties on their roles and expectations towards the organizations is the party age rather than its parliamentary or extra-parliamentary status.