Nineteen patients with renal cell carcinoma with tumor extension into the inferior vena cava (IVC) were investigated between January, 1973 and March, 1994. The patients were between 50 and 78 years old with a mean of 65.9 years. The male to female ratio was 1.7 to 1. Thirteen tumors were on the right side and 6 on the left side. In 12 patients, both nephrectomy and removal of the tumor thrombus were performed. The survival rate in the operated group was 60% at 5 years. Histologically, 7 cases were diagnosed as clear cell subtype and 5 cases as granular cell subtype. From this study, an extended operative intervention such as radical nephrectomy combined with tumor thrombectomy of the IVC with or without cavectomy was suggested in the case of renal cell carcinoma without any other metastatic lesions and histopathologically of the clear cell subtype.