An unusual case of complete anuria of 3 days'' duration resulting from obstruction of the ureteral orifices was studied. The obstruction was believed to be the result of acute edema which was a manifestation of an allergic reaction to Skiodan which had been injected for retrograde study of the urinary tract. The obstruction remained almost complete until the third day at which time it was relieved by passing ureteral catheters through each orifice. Release of the intrapelvic pressure immediately relieved the renal pain, and azotemia rapidly disappeared.