Thermal ablation is expanding as a technique to treat small renal masses. Damage to the collecting system is uncommon with either radiofrequency ablation or cryoablation. Early evidence suggests that cryoablation is less damaging to the urinary tract, and investigators have advocated the use of aggressive treatment in central tumors in contact with the renal hilum. The authors report a nonhealing urinary fistula after successful cryoablation of an exophytic upper pole renal mass in a patient with an ileal conduit. The presence of an ileal conduit may present an increased risk of urinary fistula after thermal ablation.