Sadism was measured using the Millon Clinical Multiaxial Inventory-II (MCMI-II) Scale 6B, Personality Disorder Examination (PDE) items for sadistic personality disorder, and sexual sadism criteria of DSM-IV. Psychopaths were found to be significantly more sadistic than nonpsychopaths based on the MCMI-II and the PDE. Overall, power was relatively high. Sadism did not differentiate violent and sexually violent groups. A diagnosis of sexual sadism was too infrequent for meaningful statistical analysis. Trait measures of sadism and psychopathy measures according to the PCL-R significantly and positively correlated. Results provide further empirical validity for the theoretically proposed and clinically observed relationship between sadistic traits and psychopathic personality. Additional research is recommended to explore the contribution of sadism as a trait or psychodynamic to the psychopathy construct, design better methods for the study of sexual sadism, and shed theoretical light on this form of human impulse. 32 references and 1 table