This paper examines urban health in low- and middle-income countries in relation to two sets of environmental issues. The first is persistent local environmental health burdens, and most notably the water, sanitation and housing deficiencies prevalent in the poor neighbourhoods of so many urban settlements. The second is emerging global environmental burdens that will be experienced in urban areas, and most notably those associated with climate change. The paper situates these issues within a policy-relevant framework that elucidates the strategies best able to address them. The first section of the paper considers how a health perspective can provide an alternative or complement to the dominant economic perspective on urban well-being. The second section turns to some of the transitions commonly associated with “development”, including not only the economic and urban transitions but also the demographic, health and environmental transitions. The third section examines in more detail the environmental health risks associated with deficient water, sanitation and housing. The final section examines the health risks associated with climate change.