Joint efforts by fields of public health in the last decade have advocated use of the built environment to protect health. Past involvement by public health advocates in urban policy, however, has had mixed results. Although public health has significantly contributed to health improvements, its participation in urban renewal activities was problematic. Health advocates and the American Public Health Association produced guidelines that were widely used to declare inner-city areas blighted and provided a scientific justification for demolishing neighborhoods and displacing mostly poor and minority people. Furthermore, health departments failed to uphold their legal responsibility to ensure that relocated families received safe, affordable housing alternatives. These failures have important implications for future health-related work on the built environment and other core public health activities.