Vena cava extension of renal cell carcinoma was diagnosed in 33 men and 8 women, 29 of whom had right-sided and 12 left-sided tumours. Angiography was performed in all and cavography in most patients. Computed tomography was available in 16 cases. The tumour thrombus did not reach the diaphragm in 32 patients, and extended above it in 9 cases. Macroscopically, complete cavathrombectomy was performed in 33 patients. All tumours except one were of high grade type (grades III and IV). Serum creatinine and liver enzymes were normal at the first postoperative check-up. The 5-year-survival rate in patients subjected to complete cavathrombectomy was 24%. The 5-year-survival was 33% in patients whose tumours extended to below the diaphragm, 0% in patients whose tumours extended above the diaphragm (NS), 33% in grade III tumours and 0% in grade IV tumours (NS), 33% in patients without evidence of metastases and 0% in patients with preoperative metastases (NS).