Congenital teratomas occur most frequently in the sacrococcygeal region. Most grown into a large perineo-sacral swelling that is conspicuous externally. Infrequently, the neoplasm is contained almost entirely within the pelvis in the presacral space. Congenital urinary ascites is observed in patients with obstructive uropathy; posterior urethral valves in a newborn is one of the most prominent causes of urinary ascites. We report a case of presacral teratoma leading to rupture of the urinary bladder due to outflow obstruction and causing urinary ascites. The ascites was drained, the bladder was repaired, and the teratoma was successfully excised. A review of the literature did not reveal any similar case.