The process of urbanization could be described as one of the major global environmental changes directly affecting human health today. Populations particularly affected are in developing countries where rapid urban growth has been accompanied by massive urban poverty. Urban environmental health impacts, particularly the impact on adults of an environment of poverty, are still poorly understood. Definitions of the urban environment tend to be physical, excluding the complex ramifications of a social setting of disadvantage. This paper provides a brief overview of existing knowledge on the links between environment, poverty and health in urban areas of developing countries, with an emphasis on the policy implications implied by research on health differential between groups within cities. The paper argues that urban poverty and inequalities in conditions between groups within cities present a central crisis confronting urban policy in terms of human health and quality of life. The paper suggests that definitions of the urban environment tend to consider only the physical, and not the social complexity of the urban setting. The review concludes that the scale and the complexity of the urban crisis in developing countries demands a real commitment to re-thinking the management of cities to address multiple deprivation. The paper suggests that this challenges urban professionals who continue to act with a bias towards unintegrated single sector solutions despite claims to the contrary.