In this paper the authors have analyzed the management and the outcome of 81 cases of posterior urethral valves which occurred during the period January 1972 - April 1985. 53 children presented very severe urethral valves (grade 4 according to Hendren), 28 mild valve type. All the children of the first group but two had a dilatation of the U.U.T. Vesico-renal reflux, usually severe, was present in 51 ureters; in another 50 ureters a dilatation without reflux was present. 47% of the children of the first group had a renal function within the limits of normality at the moment of presentation and the remaining 53% a reduced renal function. In 9 patients (8 under 50 days of age) a cutaneous vesicostomy according to Blocksom followed, at the age of 10-18 months, by transurethral valve destruction was done. In 6 infants, in the early part of the series, the valve was removed with a hook via the perineal approach. In 38 patients we performed a transurethral valve destruction with the n. 3 Bugbee electrode. 36 out of 53 children (68%) had exclusively a removal of the valvular obstruction. After the removal of the obstruction, 32 out of 37 non refluxing dilated ureters (86.5%) showed a clear improvement. In 7 out of 29 refluxing ureters a nephrectomy was carried out. In the remaining 22 ureters the reflux vanished in 17 and improved in the other 5. 17 children had other types of operations after valvular removal. 23 ureters in 13 patients were reimplanted, with 3 failures (13%). In the 53 children with very severe valve (grade 4) supravesical diversions were not carried out. In the follow-up of 51 children (from 6 month to about 14 years) the renal function was within the limits of normality in 74% (before the operation it was 47%). The best results were obtained in children diagnosed and treated in the first months of life. Cutaneous vesicostomy showed itself to be a very useful method of treatment in very young babies with severe complications. We observed a slight terminal urethral stricture, easily dilatable, in only 1 child. All the children over the age of 12-13 years were continent. In 28 children with mild valves, as well as transurethral valve destruction, an ureteric reimplantation was carried out with success in 5 children (8 ureters) and a vesical diverticulectomy in another 2.