This study investigated the health-related concerns of adolescents living on streets as compared to poor and privileged adolescents living with their families in Sao Paulo, Brazil. The different groups of respondents were similar in terms of individuals' fear of disease and lack of concern about health in old age. AIDS and cancer were feared by most of the respondents in the different groups, particularly because of their severity and people's vulnerability to these conditions. Health in old age was not a major concern in any of the study groups. It is suggested that health educators take into account the wide range of concerns among adolescents on the streets in order to design interventions that cater for different levels of interest and motivation. It is also argued that there is a need for health education in order to clarify misperceptions about disease transmission, prevention and treatment among adolescents from different socioeconomic backgrounds. (Contains 3 tables.)