This paper focuses on participatory urban planning as a model of urban reform and democratic invention in Brazil. Its case material regards the formulation and implementation of two sets of urban laws of very broad consequence. First, we discuss briefly the chapter on urban policy in the 1988 Citizen Constitution and the federal law that it mandates. The latter is the Estatuto da Cidade, the City Statute, from 2001, which required that 1600 cities (approximately 30% of Brazilian municipalities) either create Master Plans or reformulate existing ones according to its principles and on the basis of popular participation. Second, we focus on São Paulo’s Master Plan(2002) and Zoning Law (2004) that fulfill this requirement and on the Plan’s required revision in 2007. By examining this massive constitutionally mandated formulation of urban policy, our aim is to analyze the development of a new paradigm of urban policy that reinvents master planning.