Although all Conditional Cash Transfers (CCTs) that have been promoted in Latin America establish some kind of conditionality, there is high heterogeneity in the way they condition cash benefits. This project explores the origins of Latin America’s different approaches to designing and implementing CCT programs, based on three case studies (Argentina, Chile, and Uruguay) with different conditionality models. We use process-tracing to test four main explanations of the variation in conditionality models: partisanship, political competition, diffusion and policy legacies. This method allows us to generate systematic new evidence concerning the diverse conditionalities that characterize CCT programs in the region. More specifically, our approach advances understanding of the causal processes that lead governments to choose between different types of conditionalities. In so doing, the project contributes to the literatures on the politics of conditionality in welfare programs and on the politics of social policy in Latin America.