From 1985 to 1993, five male patients with posterior urethral valves were treated at our hospital; they included three newborns, a 32-month-old and a 10-year-old child. On initial examination, all patients showed severe bilateral hydronephrosis and hydroureter on sonographic findings, dilatation of the prostate urethra and trabeculation of the bladder wall in the voiding cystourethrogram; only one patient showed vesicoureteral reflux. Type I urethral valves were present in all patients. Retrograde transurethral ablation of the valves was performed in four patients with good preoperative renal function. The postoperative courses were smooth except for vesicoureteral reflux in one patient and systemic fungus infection in another. Reimplantation of the ureter was done for the vesicoureteral reflux, and the fungus infection was treated by amphotericin B. Cutaneous vesicostomy was performed for a newborn since the urethral orifice was small. He presented with poor renal function and ascites. Delayed antegrade ablation of the valves per vesicostomy and closure of the vesicostomy were done three months later after restoration of the renal function. Renal function returned to normal after operation in all patients, but the function of the upper urinary tract and bladder continence need long-term follow-up.