A review of 150 patients with renal carcinoma revealed that 45 per cent were hospitalized with distant metastases or tumors that were unresectable. Although the behavior of the neoplasm in the 55 per cent who were theoretically curable was generally unpredictable, longevity and survival were markedly increased in patients with tumors less than 8 cm. in size and concomitantly with other acknowledged features of low stages of the disease. Since patients can survive with tumor for long periods and metastases may occur many years after the operation prognosis must be guarded and long followup is needed to assess the results of therapy at any stage of the disease.