The authors report on a case of thrombosis of vena cava and renal vein associated with a nephrotic syndrome and complicated by a massive pulmonary embolism. Under emergency conditions, it was impossible to diagnose preoperatively a renal tumor, which is the most common cause of renal and vena caval obstruction or a thrombosis of the vena cava. Surgical treatment was carried out only because there were no arteriographic signs of renal neoplasm, and because thrombolytic treatment was contra indicated in a patient with greatly reduced vital capacity. Embolectomy was performed under cardiopulmonary by pass. The patient made a good recovery. Results of routine cardiac and pulmonary tests were normal after two months. Embolectomy must always be associated with as interruption of the vena cava, whose different forms are discussed. Partial interruptions using a De Weese clamp seems to be better tolerated than ligation.