The study findings indicate that psychotic disorders are rare among sexual murderers and not significantly different between the sexual murderers of women and sexual aggressors against women, which is consistent with the results of several previous studies. None of the sexual murderers in the study exhibited obsessive-compulsive disorder, and none of the subjects was diagnosed with a mood disorder or dissociative disorder. The authors caution, however, that all of the sexual murderers assessed for psychopathology were incarcerated after being found criminally responsible for their crimes. A more reliable study would include an assessment of sexual murderers confined to secure psychiatric facilities after having been found not criminally responsible because of a mental disorder. Sexual sadism was the only paraphilia diagnosed in a significant proportion (16.7 percent) of sexual murderers. This proportion is surprisingly low, however, given that sexual sadism is considered one of the central features of sexual murder. The most commonly encountered personality disorders among both sexual murderers and sexual aggressors were antisocial, borderline, and narcissistic disorders, which agree with the findings of a number of previous studies. A total of 101 sexual aggressors and 30 sexual murders were assessed with the Millon Clinical Multiaxial Inventory (completed by 75 sexual aggressors and 25 sexual murders). The diagnoses for axes I and II of DSM-IV were taken from the clinical files of Correctional Service Canada for all sexual aggressors and from the clinical files of the Regional Reception Centre for sexual aggressors. 5 tables and 2 case studies