A double lumen Swan Ganz balloon catheter is introduced percutaneously into the renal artery. Temporary and repeated occlusion of the artery by inflation of the balloon are combined with hypothermic perfusion of the kidney. Thus extensive nephrolithotomies can be done without time limit as in warm ischemia. The operation field is blood-less and the parenchym is protected by perfusion. There is no need for pedicle dissection or external cooling. One complication is seen when the catheter is slipping out of the artery in cases of short renal arteries and the patient is in an extremely bent operation position for intercostal approach. Ballon occlusion without perfusion is helpful in tumor nephrectomy. Preoperative embolization is not necessary when this technique is used. Embolization means an additional procedure with further complications.