The records of all patients with small cell carcinoma of the lung seen in the Division of Therapeutic Radiology at The Medical College of Wisconsin from 1971 through 1977 were reviewed. Of 69 patients (34 with limited disease and 35 with extensive disease), 35 received irradiation only, nine received local plus total-body irradiation, and 25 received irradiation plus chemotherapy. In spite of the prompt response of the tumor, 16 of 35 patients who were only irradiated failed locally. Two patients who received local plus total-body irradiation failed in the chest. Only four of 25 irradiation plus chemotherapy patients failed locally in spite of much lower doses of thoracic irradiation. Limited-disease patients who had local control by irradiation had a slight increase (29 vs 22 weeks) in median survival. Patients receiving irradiation plus chemotherapy (three with limited and 22 with extensive disease) survived for a median of 56 weeks if the local tumor was controlled and for a median of 28 weeks if there was local failure. Regardless of therapy, survival beyond the median is greatly influenced by local tumor control.