The authors describe three men, all with benign premorbid psychiatric histories, no evidence of antisocial personality disorder, and no history of violence, who impulsively committed violent crimes--including murder--while taking anabolic steroids. Structured psychiatric interviews of each man suggested that steroids played a necessary, if not primary, role in the etiology of the violent behavior. Although the men conceivably might have exaggerated their reports of the effects of steroids in the hopes of improving their legal positions, information from external sources consistently corroborated their accounts in each case. These observations raise the possibility that steroid-induced violence may pose a little-recognized public health problem.