This report is one of a series of outcome evaluation studies for parent-training procedures tailored specifically to families of preadolescent antisocial children. Referred families were screened to identify 19 problem children who were observed in their homes to be high-rate social aggressors. Cases were randomly assigned to the parent-training procedures or to a waiting-list comparison group. All but one of the latter accepted a referral for treatment elsewhere in the community. After an average of 17 hours of therapy time, the cases in the experimental group were terminated. Post-treatment observation data were collected in the homes of both the experimental and the comparison groups. The results indicated that, relative to the changes in the comparison sample, the parent-training sample showed a significantly greater reduction in the observed rates of deviant child behavior.