Six male patients in a maximum-security hospital committed acts of urethral self-mutilation by insertion of a foreign body. The characteristics of the self-mutilators and of this unusual form of self-mutilation are described. The social contagion aspects of the self-mutilation are strongly suggested by the perpetration of urethral insertion for the first time by five patients after direct personal contact with a previous urethral self-mutilator. Techniques used in the management of these patients are described. Self-mutilation evokes strong emotional responses in staff members, and proper patient management also must include attention to the needs and concerns of treatment staff.