The aim of this study was to demonstrate the effectiveness of cognitive behavioural treatment (CBT) with a focus on academic skills and conduct problems and to increase parents' educational skills in managing aggressive and oppositional behaviour in a subsequent parent training (PMT). For this purpose 18 children with a diagnosis of ADHD combined type participated in the study. In an A-B study design the effects of a 12-week treatment phase (6 weeks CBT; 6 weeks PMT) were compared with a preceding 4-week baseline. Core symptoms of ADHD, conduct problems and individual problem behaviour were assessed by weekly administration of parent and teacher questionnaires. The results indicate a significant and generalized reduction of ADHD core symptoms, conduct problems and homework problems during CBT at home and at school. PMT resulted in a further amelioration of the cited symptoms. We conclude that CBT may be a promising component in the treatment of ADHD provided that aspects of generalization are considered during the treatment. PMT may be a useful adjunct in most cases as it is effective in situations where the ADHD child still has problems of self-guidance.