Public health leadership has a clear and continuing responsibility to mobilize effective action for health across the entire range of human activity. Recognizing this broader mission and the critical importance of urbanization in relation to it, my predecessor, Surgeon General Luther L. Terry, sought the advice of a group of outstanding individuals with wide and varied experience as elected officials, scientists, health administrators and practitioners, and private citizens. This Advisory Committee on Urban Health Affairs presented its report to me in December 1965. The paper presents the findings of that committee.