What are the variety and scope of administrative challenges faced by large bureaucratic structures when they implement system-wide change? Specifically, when decision making about priorities for human immunodeficiency virus (HIV) prevention programs was decentralized by the Centers for Disease Control and Prevention (CDC) and delegated to state and local departments of health, what were the implications for public health infrastructure, work force training, resource distribution, and policy development? Using a previously developed model of effective change management, Ronald O. Valdiserri describes, from a federal agency perspective, the variety of actions that were necessary to implement and sustain system-wide changes in the planning and priority setting of CDC's publicly funded HIV prevention programs.