This article argues that clans, informal organizations based on kin and fictive kin ties, are political actors that have a profound impact on the nature of posttransitional regimes and the potential for regime durability. The article first develops the concept of "clan" conceptually. It then develops several propositions about clan politics and explores them empirically in the context of the post-Soviet Central Asian cases. These cases suggest the limits of the prevailing transitions and institutionalist approaches; these theories cannot explain regime transition in the Central Asian cases because they focus on the formal level and ignore the crucial informal actors- clans-and the informal politics that shape these cases. The distinct mode of transition, new regime institutions, and leadership and elite ideologies evident at the formal level have a very short-term effect; within five years, these cases converge toward a pattern of informal, clan-based politics. By contrast, this article draws upon the insights of the early literature on political development as well as the state-society literature to develop an alternative framework for explaining the dynamic between clans and the regime. Clan networks and clan deals penetrate and transform the formal regime in several ways-by clan-based appointments and patronage, by stripping state assets to feed one's clan network, and by crowding out other mechanisms of representation. As they undermine formal institutions, clans create an informal regime best understood as "clan politics".