Using angiography it is possible to accurately define venous extension of renal carcinomas preoperatively. Modern surgical techniques permit successful removal of the tumors and vena cava en bloc. The left renal vein can be ligated, although a syndrome of temporary renal dysfunction may occur. The long term prognosis of such patients appears to correlate best with the pathologic stage of the resected specimen and cannot be predicted by preoperative studies unless these show evidence of metastases.