Urbanization and the AIDS epidemic are both growing global phenomena that are changing the landscape of development. Their intersection is complex and has not received suffi cient attention either in the literature or in policy directives. While considerable effort has been devoted to understanding how the AIDS epidemic is impacting on national development, there has been less emphasis on learning how urbanization affects the AIDS epidemic. The key policy documents outlining strategies for strengthening the response to AIDS are no exception.1 This represents a missed opportunity to call global attention to the susceptibility to HIV associated with urbanization and, even more important, to the recognition of the potential benefi ts that urbanization could provide in AIDS responses.