Standard treatment for upper urinary tract urothelial carcinoma (UUTUC) implies the radical removal of all urothelium-lined tissue, which requires nephroureterectomy with bladder cuff removal. We report on a patient with a rare coincidence of UUTUC and horseshoe kidney in whom a preoperative angiography helped to identify and subsequently embolize an abberant isthmic feeding artery, which was located in between both collecting systems. Ischemic discoloration of the isthmus area facilitated resection and no major blood loss occurred. Preoperative superselective embolization of the isthmus as the renal split area can be an effective tool to facilitate nephroureterectomy in the case of a horseshoe kidney.