Recent literatures suggest that pulmonary embolus secondary to renal cell cancer may be more common than previously suspected. A 63-year-old man, who suffered a massive tumor embolism to the right main pulmonary artery after surgery for renal cell carcinoma with vena caval and renal vein invasion, was treated by emergency pulmonary embolectomy using cardiopulmonary bypass. Renal cell carcinoma occasionally extends into the inferior vena cava as a tumor thrombus. In such patients, removal of the tumor thrombus from the inferior vena cava has to be performed in addition to radical nephrectomy. However, the massive pulmonary tumor embolism is a major potential hazard during radical surgical resection. To prevent intraoperative pulmonary embolisms, scheduled use of cardiopulmonary bypass with the cooperation of cardiovascular surgeons is recommended in addition to the standard proximal vena caval occlusion technique of clipping and clamping.