Parents of 20 hard-to-manage children were randomly assigned to one of three treatment conditions. The first group received eight sessions of group training in behavior management skills. The second group received individual training in their homes as well as group training. The third group received group training and in-home observations, but not in-home training. Evaluations were conducted at baseline, at termination (after 16 hours of training over 8 weeks), after 6 months, and again after 2 years. The training was effective in reducing the incidence of both targeted and nontargeted behavior problems according to parents' reports and home observations. The addition of in-home training did not add measurably to the effectiveness of treatment.