The prevalence of 3 mental disorders (Depressive Disorder, Conduct Disorder and Attention-Deficit/Hyperactivity Disorder), the prevalence of mental health problems, and rates of health-risk behaviours among those with problems, along with patterns of service utilisation, are reported for 1490 adolescents aged 13-17 years in Australia. Mental disorders were assessed using the Diagnostic Interview Schedule for Children Version IV completed by parents. Parents and adolescents also completed standard questionnaires designed to assess mental health problems, health-risk behaviours and service use. On the basis of parent reports, 13% of adolescents were identified as having mental health problems, while 19% were identified as having problems on the basis of adolescent reports. Many of the adolescents with mental health problems also had problems in other areas of their lives. Only 31% of those identified by parents as having mental health problems and 20% of adolescents who identified themselves as having problems, had attended a professional service during the 6 months prior to the survey. School counselling was the service most frequently attended. Clinical and population health interventions must take into account the presence of co-morbid problems and low rates of health service usage reported amongst adolescents with mental health problems.