Objective. The objective of the study was to evaluate the mechanical performance and the patient/partner satisfaction of the GFS Mark II inflatable penile prosthesis (IPP). Method. A total of 138 patients had GFS Mark II IPP implants between October 1988 and December 1991 with a follow-up of twelve to fifty months (mean 31.7 months) were studied. Each patient was evaluated for prosthesis performance and each patient/partner satisfaction was evaluated by a questionnaire and personal interview. Results. There was only one prosthetic mechanical problem which involved the tubing. There were seven problems requiring explantation; two of which were postoperative infections. Thirteen patients required an addition of normal saline through the resipump as an office procedure. Ninety-three percent of the patients and 98 percent of the partners reported satisfaction with the use of the prosthesis. Men who had a previously inserted penile prosthesis replaced with the GFS Mark II IPP preferred the GFS over the malleable and the self-contained prosthesis, but there was no conclusive preference between the different IPPs. Conclusions. This study concludes that the GFS Mark II connectorless IPP has shown few mechanical problems over a four-year period and has a good patient/partner satisfaction. This prosthesis has the additional feature of the resipump to adjust the fluid volume as an office procedure when required.