Survival factors of 86 patients with metastatic renal cell carcinoma were studied by computer analysis. Cumulative survival was 53 per cent at 6 months, 43 per cent at 1 year, 26 per cent at 2 years and 13 per cent at 5 years. Survival was influenced favorably by confinement of metastases to the lungs, by the absence of local recurrence or persistence of tumor and by a longer interval free of disease after removal of the primary tumor. Medical therapy improved survival during the first year after diagnosis of metastases but no objective regression of tumor was observed. Excision of metastatic foci significantly improved survival for up to 5 years (p less than 0.05 and p less than 0.02) after which most patients died of recurrence. Palliative or adjunctive nephrectomy in patients with metastases was associated with a 6 per cent mortality rate but it increases survival over other patients with metastases at the time of diagnosis of renal carcinoma who did not undergo nephrectomy. This difference was owing to patient selection and survival of those who had adjunctive nephrectomy was no greater than that of the study population as a whole. However, based on the factors that were associated with improved survival palliative nephrectomy may be beneficial when a limited number of metastases treatable by excision or radiation therapy are present, when effective systemic therapy exists or when the primary tumor produces severe symptoms.