Erectile impotence can now be treated with a device that mimics a natural erection. Between 1973 and 1977, we implanted an inflatable prosthesis in 245 men (235 with organic impotence and ten with psychogenic impotence). Of these, 234 are able to use the device to their satisfaction; no failures have occurred in the 152 cases treated in 1976 and 1977. The success of this treatment rests in part on the careful selection of patients by a team--a urologist, a sleep researcher, a psychologist, and a psychiatrist--each evaluating the patient independently. Our experience suggest that erectile impotence may be more common than generally believed and that impotence from organic causes may account for a greater percentage of cases than formerly thought.