This study attempted to replicate previous findings that indicated that preschool-aged children with significant externalizing problems are more likely to have insecure attachment relations than nonproblem peers (Speltz, Greenberg, & DeKlyen, 1990). Fifty children (ages 3–6) and their mothers participated; 25 referred to a child psychiatry clinic for one of the DSM-IIIR Disruptive Behavior Disorders, and 25 matched comparisons without externalizing behavior problems. Attachment was measured at the time of referral using two separation and reunion sequences in a clinic context. We found that 80% of the clinic-referred children were classified as insecure, whereas only 28% of the comparisons were so classified (p <.001). Further, a high percentage of clinic insecure children showed a controlling pattern of attachment. Thus, the present study, with improved methodological rigor, provided an almost exact replication to previous results. The discussion focuses on what contribution attachment research can provide to a developmental psychopathology perspective on early externalizing disorders.