The role of reduction cystoplasty in the management of severe prune belly syndrome is controversial. From 1973 to 1990, 11 boys with severe prune belly syndrome underwent comprehensive urinary tract reconstruction, including overlapping reduction cystoplasty. Followup ranged from 1.5 to 18 years and 6 boys are now older than 18 years. Nine had sepsis or progressive renal failure as neonates; 7 had upper tract diversion as an initial procedure, of whom 2 have chronic renal failure. Currently 9 boys are voiding, including 1 who could not void preoperatively, with less than 50 cc residual after double or triple voiding. One boy underwent transplantation to an ileal conduit and 1 continues on intermittent catheterization. In the 9 cases in which bladder volume data were available average reduction in volume at operation was 52%. At an average of 7.7 years later (range 1.5 to 14) bladder volumes corrected for age were essentially unchanged or greater than corrected preoperative volumes. Since reflux was corrected in 7 of 9 boys it cannot account for the redevelopment of large bladder capacities (range 740 to 2,300 cc). In cases of the prune belly syndrome reduction cystoplasty has helped to improve voiding and minimize infection during early childhood but it does not seem to decrease bladder capacity or improve voiding dynamics in the long-term.