The preliminary data from this cross-sectional investigation support the author's efforts to fill the "measurement gap" by developing a reliable and valid instrument for identifying antisocial beliefs and attitudes. In the school sample, the original seven subscales that composed the new ABAS items were found to be internally consistent. Nonetheless, substantial shared variance between scales indicated the need for a factor analysis of the new ABAS items. A meaningful internal structure consisted of three factors: Rule Noncompliance, Peer Conflict, and Severe Aggression. The revised ABAS captured unique variance in self-reported antisocial behavior in the sample of children who ranged in age from 10 to 17. The Rule Noncompliance factor was predictive of self-reported antisocial behavior at all ages or grades sampled. Peer Conflict had an independent and additional predictive effect on antisocial behavior during early to mid-adolescence. The Severe Aggression factor failed to contribute to the prediction of antisocial behavior at any grade level, perhaps due to the low frequency with which Severe Aggression items were reported. Along with a self-reported measure of antisocial behavior, the ABAS was administered to 425 school children ages 10-18. The ABAS is a new instrument for measuring antisocial thinking in older children and adolescents. It is developmentally sensitive and broad-based in assessing domains based in the empirical literature on childhood conduct problems and delinquent behavior. 8 tables, 1 figure, and 87 references