Purpose: The AMS700 Ultrex* penile prosthesis is an example of the design changes that penile prostheses have undergone to improve mechanical reliability. Few studies have reviewed an overall experience with the AMS700 Ultrex prosthesis. We review patient outcomes, surgical complications, and Ultrex cylinder intermediate term mechanical reliability and function. Materials and Methods: Between March 1990 and November 1994, 145 patients 32 to 79 years old (mean age 58) underwent insertion of an AMS700 Ultrex penile prosthesis. At a followup of 6 to 62 months (mean 42) patients were evaluated with a retrospective clinical record review, and patient and partner questionnaires. Results: From the clinical record review of 145 patients our malfunction, reoperation, infection, erosion, major complication and minor complication rates were 8, 13, 2, 3, 13 and 7%, respectively. Patient responses to our questionnaire showed that 85% were satisfied overall, 85% had durable and reliable implant function, 86% had a sustained level of satisfaction with the implant and 83% remained satisfied after a revision for malfunction. Overall, partner satisfaction with the implant was 76%, and 42% reported maintenance of a good or improved nonsexual relationship after prosthesis implantation. Conclusions: Our data demonstrate the intermediate term mechanical reliability and function of the AMS700 Ultrex penile prosthesis, and high patient and partner satisfaction with this implant.