To date, assessments of the prevalence of mental health problems in young offenders have largely focused on incarcerated samples. This paper describes a quantitative study of a sample of 47 male young offenders under the supervision of an inner city Youth Offending Team. A semi-structured interview, modified from previous studies, was used to investigate the type and frequency of psychosocial and health problems they experienced. The results were compared with data from a random community sample of 38 male adolescents interviewed in a comparable way. Young offenders reported more psychosocial problems at a statistically significant level (including depression/misery, excessive worry and problematic substance use), as well as higher life-time rates of head injury, than adolescents in the community sample. Levels of problematic substance use and exposure to head injury continued to differentiate the groups when offenders in custody were removed from the analyses. The findings are discussed in relation to previous research and implications for service delivery.