Forty-six patients have undergone implantation of a penile prosthesis using the Mentor inflatable device. All patients are at least six months postimplantation, with the average follow-up being twenty-one months. Six patients have required reoperation due to technical problems, but there have been no mechanical failures. This low mechanical failure rate greatly enhances the attractiveness of this type of penile prosthesis when comparing it with the semirigid devices.