Health systems in South America still support segmentation, privatization and fragmentation. Health reforms of the structural adjustment programs in the 1980s and 1990s in South America followed different purposes and strategies ranging from privatization, commodification and state intervention for the implementation of a national public health service with universal access as a right of the citizens. Since the 2000s, many countries have expanded social policies, reduced poverty and social inequalities, and improved access to healthcare. This article proposes to discuss the health systems in South America from historical and political backgrounds, and the progress from the reforms in the last three decades. It also presents the three paradigmatic models of reform and their evolution, as well as the contrasts between universal coverage and universal systems. Finally, it presents current strengths and weaknesses of the twelve South American health systems as well as current opportunities and challenges in health for UNASUR.