Because of the enormity of the HIV-AIDS epidemic and the urgency for p
reventing transmission, HIV prevention programs are a high priority fo
r careful and timely evaluations. Information on program effectiveness
and efficiency is needed for decision-making about future HIV prevent
ion priorities. General characteristics of successful HIV prevention p
rograms, programs empirically evaluated and found to change (or not ch
ange) high-risk behaviors or in need of further empirical study, and e
conomic evaluations of certain programs are described and summarized w
ith attention limited to programs that have a behavioral basis. HIV pr
evention programs have an impact on averting or reducing risk behavior
s, particularly when they are delivered with sufficient resources, int
ensity, and cultural competency and are based on a firm foundation of
behavioral and social science theory and past research. Economic evalu
ations have found that some of these behaviorally based programs yield
net economic benefits to society, and others are likely cost-effectiv
e (even if not cost-saving) relative to other health programs. Still,
specific improvements should be made in certain HIV prevention program
s.