Nearly all the youth met DSM-III-R conduct disorder criteria at the time of their crimes. Data were collected using the DSM- III-R Diagnostic Interview for Children and Adolescents, the Schedule for Nonadaptive and Adaptive Personality, the Revised Psychopathy Checklist, and an author-designed clinical interview. Results showed the presence of personality disorders and moderately high psychopathy scores at follow-up were common. Two- thirds of the young people reported the presence of violent sexual fantasies before their crimes. Weapons, most often knives, were used by these juvenile sexual murderers to kill known victims in a majority of the cases. They usually acted alone and selected a low-risk victim. Six of the 14 juveniles were under the influence of mind-altering substances at the time of their crimes, either marijuana or alcohol or a combination of the two. Twelve youths chose a victim of the same race. Vaginal intercourse was the most common form of sexual assault. Evidence indicated the youths planned the murders, targeted their victims, and displayed control at the crime scene. Overall, findings suggest juvenile sexual murderers represent an emotionally and behaviorally disturbed population with identifiable psychopathology, personality disturbances, and criminal patterns. 34 references, 1 table, and 2 figures