Implantation surgery was performed twelve times in eleven patients with organic impotence, mainly due to radical cystectomy and prostatectomy against malignancy, between March, 1982 and April, 1987. A self-contained type prosthesis (AMS Hydroflex(TM] was used in 7 cases, reservoir type inflatable prosthesis (AMS 700TM) in 2, malleable semirigid type (ESKA-Jonas Silicon Silver(TM) Trimming Tip Version) in 2, and nonmalleable semirigid type (Fuji system Finney type) in 1 case. In the last case, the prosthesis was replaced by AMS Hydroflex 4.5 years later at patient's wish. Excellent results and good patients' acceptance were gained with inflatable-type prosthesis (AMS 700 and Hydroflex) in 7 out of 8 cases (88%), whereas concealment problems were produced by semirigid type prosthesis (Finney and Jonas). Experience with AMS Hydroflex penile implantation is reported for the first time in the Japanese literature. Intraoperatively, it was sometimes difficult to implant a pair of Hydroflex rods into both of the corpus cavernosum. Postoperative perineal pain was almost constantly seen and in one patient, penile edema continued for three weeks and subsided spontaneously in two months. In another patient, the length of the prosthesis (15 cm) was short, and exchange to the longer one (17 cm) was necessary. In this patient, the longer Hydroflex caused erosion of the glans to necessitate its removal on one side. From our experience, the diameter (11 mm) of the Hydroflex seems to be too big for the average Japanese patient. The operative procedures and results of each kind of the prostheses are briefly discussed.