Eleven groups of students performed a 24-session intervention based on Aggression Replacement Training (ART) as part of their further education programme. Subjects were 65 children and young people with varying degrees of behavioural problems. Forty-seven subjects received the ART programme. Eighteen received standard social and educational services and served as comparison subjects. Social problems and skills were assessed before and after the ART intervention using multi-informant instruments (SSRS, CADBI, HIT, CBCL). Informants in the ART group indicated significant improvement following the intervention, both in terms of increased social skills and reduced behavioural problems; in contrast, informants in the comparison group did not generally indicate improvement. (Contains 3 tables.)