Nine boys whose age ranged from 5 days to 3 months with urinary ascites were managed in Beijing Children's Hospital. All of them presented with gradual abdominal distension from birth, 5 had dripping of urine, the 5-day old new born had anuria since birth. In 2 other infants one had cystostomy and the other, ureterostomy before admission. Urinary ascites was confirmed by abdominal paracentesis. Intravenous pyelography (IVP) and Voiding cystourethrography (VCUG) in 7 cases showed bilateral hydroureteronephrosis and dilatation of the posterior urethra consistent with congenital posterior urethral valves. The 40-day old infant who had cystostomy followed subsequently by vesicostomy is still waiting for ablation of the valves. The remaining 6 were managed by 2 stage operation, 5 had vesicostomy first, one; ureterostomy. They had valves ablation either through urethra or bladder at the age of 3 months to 2 years old. Urinary ascites disappeared spontaneously after urinary drainage. Two patients died; one due to dehydration after drainage of the obstructed renal pelvis, the other (in 1977) had no urinary drainage for obstructed urinary tract.