This compendium presents a review of the evidence of the effectiveness of behavioural components of combination prevention. It attempts to provide a technical basis for the inclusion of behavioural interventions in a combination HIV prevention framework and to support the prioritization of specific behavioural prevention activities for different populations. The document aims to reach policy-makers, programme managers and implementers, civil society advocates, United Nations (UN) system staff, and other individuals and groups with an interest in developing effective and comprehensive HIV prevention programmes.