This article argues that the conservation movement provided a conceptual and organizational model for New Deal—era urban professionals eager to motivate federal and local investments in city improvement. During a period when research and policy for the scientific management of natural resources attracted broad support, city planners and real estate appraisers seeking professional legitimacy in a nation recently recognized to be urban saw in conservation new possibilities for articulating the urgency of their professional goals. Focusing on efforts by the National Resources Planning Board, Home Owners Loan Corporation, and Federal Housing Administration to transform ecological theories of cities from the social sciences into a national movement for urban community conservation offers insights into the impact of Americans' enduring preference for nature over cities on urban history during the New Deal.