This study reviewed the surgical therapy for lung metastatic foci of renal cell carcinoma. During the 14 years from 1977 to 1991, lung metastatic foci were removed in 10 patients with renal cell carcinoma at our hospital. Six of them died of cancer and four are alive. The prognosis tended to be better the longer the interval from nephrectomy to lung metastasis. Neither the number of metastatic foci nor the surgical technique produced any difference in the prognosis. The prognosis tended to be better for patients with clear cell tumors than for those with granular cell tumors. For the treatment of lung metastasis of renal cell carcinoma, since we have no better therapy than surgical removal at the present, it is our duty to attempt to improve the prognosis of patients by the resection of metastatic foci whenever possible. However, the use of adjuvant therapy such as interferon should be considered, and the indications for operation and the timing of surgery reviewed.