OBJECTIVE: To review evaluations of interventions in developing countries targeting three groups most at risk of becoming infected with HIV: young sex workers, young injecting drug users and young men who have sex with men. METHODS: A systematic literature review was undertaken to identify programmes in developing countries targeting young people in the three selected groups most at risk from HIV. We also identified programmes directed at young people in developed countries as well as programmes in developing countries that targeted these three population groups but that did not differentiate between young people and adults. FINDINGS: Young people 10 to 24 years of age represent a large proportion of the population most at risk of becoming infected with HIV in developing countries. Despite this fact, well documented evaluations of interventions that target these groups are scarce. However, there is evidence of effectiveness for programmes that are facility-based and use outreach to provide information and services to at-risk young people. CONCLUSION: There is growing evidence from developing countries of successful interventions that target groups most at risk from HIV, and these programmes should be widely implemented provided that they are carefully planned and monitored and have a strong evaluation component. However, there is an urgent need to disaggregate data by age in order to determine how effective these programmes are in reaching young people and to better understand the specific needs of at-risk young people as opposed to older age groups.