We report two rare cases of delayed ureteral fistulas which occurred one month following rectal amputation. Case 1 was a 52-year-old male who underwent abdominal perineal resection of the rectum. One month after surgery, the patient had a paralytic ileus. Computed tomographic (CT) scan and drip infusion pyelography showed left ureteral fistula and a large pelvic urinoma. Because retrograde placement of a double-J stent was unsuccessful, antegrade placement of the double-J stent was performed. The fistula and urinoma healed soon after the placement of the double J stent. Case 2 was a 43-year-old male who underwent abdominal sacral resection of the rectum. One month after surgery, a large amount of urine began to drain from the perineal wound. CT scan and retrograde pyelography showed a right ureteral fistula and a large pelvic urinoma. There had been temporary improvement in the discharge without the treatment of the ureteral fistula, only for it to return more profusely. Because placement of a double-J stent was unsuccessful, right percutaneous nephrostomy was performed, after which, a right ureterocysto-neostomy (Boari flap method) was performed. We advocate the initial use of the double-J stent or percutaneous nephrostomy in ureteral fistula. This approach is simple and may cure the fistula. If unsuccessful, it will not hinder subsequent open surgery.