The political science literature reflects two viewpoints regarding the formation of party systems in post-Soviet societies. Scholars drawing on traditional theories of party formation usually argue that the formation of institutionalized party systems in post-Communist states will be an extended process. However, newer studies reveal that parties, partisan support, and even party systems may form relatively quickly.To illuminate this debate, we offer analysis of both mass and elite cross-temporal data from Russia, Ukraine, and Lithuania. These data reveal a rapid rise in partisanship, strong partisan voting in parliamentary elections, a sharp differentiation on issues between members of various party blocs, a high degree of issue cohesion among those who identify with a given party, and a strong correlation between the policy views of elites and ordinary citizens identifying with the same party. In short, the evidence strongly supports the conclusion that party systems are developing in the post-Soviet societies.