The efficacy of mianserin in treating adult depression is now well established. Since there are no publications concerning the use of mianserin in children, the authors set up an open pilot study of 110 depressed children and adolescents aged 8-19 years. The average dose of mianserin was 1 mg/kg/day. Efficacy of treatment was noticeable by the end of the first week and was maintained throughout the 60 day study period. Evaluation was based on both clinical observations and changes in scores obtained from 80 subjects. Side-effects were minimal leading to temporary withdrawal of treatment in only seven cases. The profile of mianserin in children and adolescents is similar to that of adults. It is an antidepressant with an anxiolytic component, and has a regulating effect on sleep. In view of its efficacy, compliance, and the very low incidence of side-effects, mianserin appears to be a useful treatment for depression in children and adolescents. The results of this open study justify the development of further controlled studies.