The advantages and disadvantages of the use of DSM-III in childpsychiatry are considered. Where relevant DSM-III is compared with the ICD-9 as far as childhood and adolescent psychopathology is concerned. In classifying children and adolescents developmental issues play an important role. Specific qualities that are required of a classification system for use in child psychiatry are considered. In this respect, because of factors inherent to a system that is categoral and based on adultpsychopathology, DSM-III provider only limited solutions. Nevertheless there are many factors in favor of DSM-III. Especially the existence of a separate childhood and adolescent section and of clearcut (though sometimes arbitrarily chosen) diagnostic criteria makes it a gain to childpsychiatry.