Radiofrequency (RF) ablation is a feasible option for treatment of renal tumors when definitive tumor resection is not performed. Renal hilar and ureteral masses are generally more difficult than peripheral renal tumors to approach with RF ablation because of the higher associated risks of injury to the hilar vessels and the collecting system. This report presents a case of RF ablation of transitional cell carcinoma of the ureteropelvic junction, performed successfully for intractable hematuria. Significant injury to the uroepithelium was avoided by the concomitant use of a cold saline infusion into the collecting system of the kidney.