The article is devoted to the social characteristics of the Civic Parliamentary Club (OKP). OKP played a key role in the systemic transformation in Poland between 1989 and 1991. The first part of the paper discusses its socio-demographic composition and the second part describes its specific sociological features. OKP has many socio-demographic characteristics of the political elite and also some specific features related to its roots in the Solidarity movement and channels of recruitment. However, its social features are very specific. These are: 1) a sense of mission associated with its place in the process of the systemic transformation; 2) awareness of being the political representation of Polish society due to the great social support experienced and the electoral victory; 3) specific political ethos originating in the period of underground activity. On the one hand, these features helped OKP deal with new and difficult challenges. On the other hand, they strongly determined the vision of the world, hierarchy of tasks, and reactions to social and political events.