During the last 6 years 24 sigmoid colon neobladders were constructed at our institute according to a surgical technique that provides for an optimal spherical configuration of the orthotopic reservoir. All patients underwent radical cystectomy for locally advanced or superficial recurrent bladder cancer. The surgical complication rate was minimal. Mean followup was 38.3 months (range 7 to 70). Patients were evaluated at 9 and 18 months with urodynamic tests. Daytime continence was achieved in 20 of 21 (95.2%) and in 16 of 17 (94.1%) patients, respectively. Nocturnal incontinence was noted in 9 of 21 (42.8%) and 5 of 17 (29.4%) patients. The mean neobladder capacity was 414 cc and 492 cc, respectively. Endoluminal pressure at the maximum reservoir capacity was 31 cm. water (range 23 to 54) and this did not change significantly at 18 months. Minimal post-voiding residual volume was evidenced in all but 1 patient and was maintained at 18 months. Our modified sigmoid colon neobladder is an easy surgical procedure that provides satisfactory total bladder replacement in select patients.