Results indicate that 48 percent of involuntarily inpatients were 16-17 years old and 62 percent had psychotic disorders. Twenty-sex percent of inpatients with involuntary legal status were voluntarily admitted. Regional differences of involuntary treatment were rather modest. Psychotic disorders, suicidal acts, and substance use disorders were independently associated with involuntary legal status. Most of the recent research on involuntary psychiatric treatment deals with adult samples. The present national study provides information on the involuntary psychiatric treatment of adolescents in Finland by exploring prevalence rates, regional differences, and a wide range of factors including demographic, family, ICD-10 diagnosis, functional level, levels of suicidality, and propensity for violence associated with the involuntary treatment of adolescents. The study, carried out in January 2000, concerned all the child and adolescent psychiatric inpatients treated in the wards (n=69) in Finland on the chosen day. Tables, references