This paper describes the neo-institutional approaches of transaction cost economics, agency theory, and property rights analysis and summarizes efforts by economists to apply these concepts to cooperatives. Several problems intrinsic to the cooperative organizational form and its property rights structure are reviewed. These problems have been hypothesized to affect the comparative economic efficiency of cooperative firms and have led to the development of life cycle models seeking to explain the formation, growth, and eventual decline of cooperatives as markets evolve. In this context, statistical analyses of the comparative efficiency of cooperatives and ex post studies of cooperative conversions are surveyed.