The evidence-based approach to health promotion and disease prevention is growing in many public health sectors, including HIV behavioral prevention. This approach is based on utilizing relevant and rigorous scientific evidence, most appropriately identified through a systematic research synthesis process. With regard to HIV behavioral prevention, this research synthesis process provides decision makers and prevention planners with the evidence base and recommendations they need to translate proven scientific research into practice. The Center for Disease Control and Prevention's HIV/AIDS Prevention Research Synthesis Team conducts such research synthesis activities to help improve HIV behavioral prevention efforts. The team's recent systematic review of the literature during 2000 to 2004 identified HIV behavioral interventions with the best scientific evidence of efficacy, called best-evidence behavioral interventions. Challenges still exist, however, for determining which of these interventions should be disseminated and implemented. Once translated into practice, if these best-evidence behavioral interventions are further evaluated for effectiveness, these findings and, perhaps, the synthesis of such findings can be used to further improve HIV behavioral prevention in the field.