We modified Studer's bladder substitute technique and constructed continent urinary reservoir for 7 patients with bladder tumors after transprostatic cystoprostatectomy. Studer's bladder substitute technique is characterized by both a tubular isoperistatic proximal limb of 20 cm of the ileum in continuity with the pouch constructed using the detubularized ileum and the ureters reimplanted into the proximal part of the limb using a simple lateral anastomosis of the ureters to the end of the limb. Our modifications, transprostatic resection, was that distal one third or fourth of the prostate was left after cystoprostatectomy followed by either enucleation of the whole residual prostatic tissue including the urethra (type II) or sharp resection of the tissue leaving the urethra (type III). A small hole in the lowest part of the pouch was anastomosed either to the residual prostatic capsule (type II) or to the residual prostatic urethra (type III). Our modified Studer's technique was simple, easy to perform, and had low risk of massive bleeding especially from the central vein overlying the appex of the prostate. Clinical results were as follows; 1) all patients were satisfied with the passing of their urine per urethra without any cutaneous stoma, 2) no patients had clinical signs of pyelonephritis after discharge, 3) urine was not infected.(ABSTRACT TRUNCATED AT 250 WORDS)