The city is, at once, a center for disease and poor health and also a place for hope, cures and good health. From the earliest times, the city has attracted the poor and been the target of the plague, as well as war. Likewise, the health care industry has always been part of the economic base of cities - from Lourdes, in France, to Rochester, Minnesota, to megacities around the world. With its highly disproportionate share of health resources, e.g., hospitals, physicians, nurses and social services, the big city is a center of excellence in medicine. Yet, as Richard Horton, editor of The Lancet once noted, "For all of its rational efficiency and benevolent intent, the city is likely to be the death of us." Are cities socially infected breeding grounds for disease? Or do they represent critical spatial entities for promotion of population health? I propose to begin with a global view of urban health and disease and the challenge this poses for public health today. Next, I examine some evidence for the hypothesis that population health in cities is relatively poor. Finally, I suggest that the more pertinent question is not whether the city is unhealthy or healthy but rather the extent to which we can alleviate the problems posed by inequalities of income and wealth - in the city as well as outside of it.