ABSTRACTOrganizational models for public-private partnerships in public irrigation in BrazilThis paper aims to evaluate existing and proposed organizational models for public irrigation perimeters (PPI) in Brazil’s semi-arid region. In a period of change in agriculture and the remodeling of public investment with the employment of mechanisms for public private partnerships, alternatives to the organizational architecture and PPIs begin to emerge. The study uses the new institutional economics and its variations of transaction cost economics and institutional environments as a basis for analysis. Interviews with selected potential investors reveal that the contractual model of PPI tends to be the most feasible, both from the conceptual point of view and from the perspectives gleaned from the private sector. However, exceptions are made in the contractual arrangements between agents as a way of ensuring the development of the perimeters and questions about the limits of public action.