The Centers for Disease Control and Prevention (CDC), in coordination with 65 states, cities, and territories, implemented HIV prevention community planning beginning in 1994. This large scale innovation in public health planning has involved tens of thousands of professionals and community residents. Though a single case study, Michigan provides a strong test of the implementation of this national prevention planning model because of the state's decentralized approach to HIV prevention community planning involving several hundred residents. A decentralized approach to community planning promises to maximize participation and the sharing of leadership as well as obstacles to community planning. Here, the CDC Guidance for community planning is contrasted with empirical observation of implementation in Michigan. We conclude that the high expectations for a decentralized approach to HIV prevention community planning can be best achieved when a distinction is drawn between information-seeking tasks and decision-making tasks. We recommend that information-seeking tasks be centrally coordinated, and that decision-making tasks be decentralized, to most fully achieve the potential of HIV prevention community planning.