Recent political science literature reflects a growing controversy regarding the formation of political parties and party systems in post-Soviet societies. The eventual outcome of the controversy holds implications for our basic understanding of how party systems form and the role parties play in developing democracies. The substantive debate is focused on the questions of whether or not the political parties that have emerged in the newly independent states of the former Soviet Union exhibit the types of political characteristics that allow us to conclude that they constitute a competitive multi-party system. Two distinct camps have emerged on either side of this query. One set of scholars, drawing upon traditional theories of party formation, argue that the formation of institutionalized party systems in post-Communist states will be a long and arduous process because these societies lack previous multi-party socialization. They see the current post-Soviet parties as ephemeral, lacking a firm foundation in policy preferences, thus reflecting nothing more substantial than a fan club for the party's leader. On the opposite side of the argument, recent research reveals a rapid rise in the proportion of post-Soviet citizens who identify with a political party and who vote for the party with which they identify. To date the empirical evidence presented in this debate, on both sides, has been limited and inconclusive. This investigation provides the first comparative data on Russia, Ukraine and Lithuania that incorporates directly comparable evidence on the level of institutionalization currently attained by party organizations, parties in the electorate and the parties in government. Prior research of the investigator provides the data on parties in the electorate and in government. This study carries out a systematic study of parties as organizations. Information on party structures and the attitudes of party activists is obtained through face-to-face survey interviews with 400 party activists and leaders in each of Russia and Ukraine, and 200 party activists in Lithuania. The resulting dataset provides the first comprehensive examination of party organizations in these three post-Soviet societies. The data provide a benchmark for future studies of party development in these new democracies. The dataset will be of great use to scholars interested in political party emergence in new democracies of the former Soviet Union.