While there has been increased attention to youth-friendly reproductive health services, little research has been conducted among adolescents in developing countries to assess what characteristics of reproductive health services are most important to them. Large scale population-based surveys were carried out among youth in Kenya and Zimbabwe. A list of characteristics that programmers often think of as youth-friendly was read to respondents, after which they were asked to assess the importance of those characteristics in choosing their reproductive health services. Adolescents rated confidentiality, short waiting time, low cost and friendly staff as the most important characteristics. The least important characteristics included youth-only service, youth involvement and young staff, suggesting that adolescents do not prioritise stand-alone youth services such as youth centres, or necessarily need arrangements particular to youth such as youth involvement. The findings imply that most existing clinical services, even in the most resource-poor settings, are in a position to improve their level of youth friendliness.