This article examines rationales forpublic intervention in health insurance markets from theperspective of public economics. It draws on the literatureof organizational design to examine alternative publicintervention strategies, including issues of contracting,purchaser provider splits, and regulation of competition.Health insurance reforms in four Latin American countriesare then considered in light of the insights provided by thetheoretical literature. This article addresses the role ofgovernment in spreading and reducing health risks withparticular emphasis on the design and organization of therelevant institutions in Latin America.