The paper contributes to the debate on the trends of sprawl and their consequences in Latin American megacities. Sprawl, as the expansion of urban areas into the surrounding countryside, has covered land more quickly than any previous form of urbanization. In Latin American megacities, sprawl occurs in a distinct context. Latin America is the most urbanized region in the world. At the same time, the population is more heavily concentrated in its primate cities than anywhere else. With Mexico City, Sao Paulo and Buenos Aires, the region has apparently three among the ten largest cities in the world. However, after decades of excessive growth, urbanization in Latin America has reached a turning point. While the rural-urban migratory flows slowed down in the last decade, intra-metropolitan mobility and the spatial, demographic and socio-economic differentiation of the population of large cities started to increase. Using Santiago de Chile as case for inquiry, it examines the size and structure of spatial expansion and the land use patterns of urban sprawl over the past two decades. It offers an assessment of this trend against sustainability principles with a special focus on land use conflicts and protection of human health. Based on this review, it draws some lessens on the critical features that result from sprawl for present and future growth of the city. The paper derives from research in an ongoing initiative on the 'Risk Habitat Megacity' in Latin America. It provides input for a debate on emerging forms of urban sprawl, as well as indicators and thresholds for sustainable land use and urban expansion. It further links to the discussion on appropriate management strategies, for example smart growth.