Significant controversy surrounds the diagnosis of sexual sadism. Research suggests that many characteristics attributed to sexual sadists fail to differentiate sexual offenders with and without this diagnosis. Furthermore, when there are differences between sadists and nonsadists, “sadistic” features are frequently associated with nonsadists. Finally, diagnosticians appear to use idiosyncratic methods to diagnose sexual sadism. These findings raise concerns about the reliability and validity of a diagnosis of sexual sadism, particularly with respect to how professionals conceptualize this diagnosis. This study examines how professionals understand the relative importance of behaviors associated with sadistic versus nonsadistic sexual offending. Professionals rated behaviors according to their “essentialness” for this diagnosis. Results show that professionals rated behaviors associated with three out of four conceptualizations of sexual sadism as significantly more essential to making a diagnosis of sexual sadism, compared to behaviors associated with nonsadistic sexual offending. Results suggest that professionals reliably dis- criminate between sadistic and nonsadistic offense behaviors.