The present study compared the effects of a cognitive-behavioral therapy with those of a supportive/psychodynamic therapy in a psychiatric dayhospital for the treatment of conduct-disordered youth (mean age 10 years 8 months). Subjects were diagnosed conduct-disordered and randomly assigned to one of two orders of the two individual treatment conditions in a crossover design. Dependent measures included indices of psychopathology as well as measures of prosocial behavior and were gathered from multiple sources. The cognitive-behavioral treatment led to significant improvements on teacher's blind ratings of classroom behavior (e.g., Self-Control Rating Scale) indicating a reduction in impulsivity, as well as on measures inidcating increases in appropriate behavior and adaptive functioning (e.g., Child Behavior Checklist). Both treatments produced some significant gains (teacher ratings of externalizing problems using the Child Behavior Checklist, and hyperactivity using the Conners Teacher Questionnaire), and some dependent measures did not evidence therapeutic change. Some of the cognitive-behavioral program's positive effects were more pronounced after its second administration. Normative comparisons, used to attempt to address clinical significance, were conducted and reported. The implications of the findings and the need for future research are discussed. © 1990 Plenum Publishing Corporation.