Although HIV prevention researchers have conducted numerous controlled outcome studies to evaluate the effectiveness of theory-based interventions aimed at reducing HIV risk behaviors, many HIV risk reduction interventions are conducted not by researchers but by staff in local health departments or community-based organizations (CBOs). Despite their widely recognized role in slowing the spread of HIV, very few attempts have been geared toward understanding the programmatic and organizational characteristics of their HIV prevention efforts. The Centers for Disease Control and Prevention's Characteristics of Reputationally Strong Programs project identified and profiled 18 innovative, community-based, HIV prevention programs viewed by community partners as successful. The aim was to determine common features of the programs that could be widely applied to improve HIV prevention research and programs. Results indicated that several common intervention characteristics and organizational characteristics, including agency support and staff commitment, played significant roles in the success of reputationally strong programs. (Contains 3 tables and 1 footnote.)