Urinary ascites is most commonly seen in fetuses and newborns with obstructive uropathy. The majority of cases are associated with lower urinary tract obstruction, such as posterior urethral valves. In this report, we present a unique case of neonatal urinary ascites caused by congenital supravesical obstruction. To date, neonatal urinary ascites secondary to bilateral mid-ureteral stenosis without a history of antenatal diagnosis has not been reported.