Six patients operated on for renal cell carcinoma with vena caval involvement were prospectively studied. The mean age of the four men and two women was 58 (range 51-77) years. In four of them the tumour was excised during cardiopulmonary bypass and deep hypothermic circulatory arrest. The operation was radical in three of these patients and palliative in one. There were no major complications or deaths during hospitalisation averaging 9 (7-17) days. The mean follow-up was 9 (4-14) months, during which two patients had died of metastatic disease. The surgical approach with cardiopulmonary bypass and deep hypothermic circulatory arrest is well tolerated and can be used to facilitate complete tumour thrombectomy, with low operative risk. Need for caval tumour thrombectomy was found in 5% of all patients with renal cell carcinoma during the study period.