One-hundred seventy-three patients with limited small cell lung cancer were included in three consecutive protocols alternating radiotherapy and chemotherapy. The alternating schedule consisted of six courses of chemotherapy (doxorubicin, VP16213, cyclophosphamide, and methotrexate in the first protocol; methotrexate being replaced by cisplatinum in the other two protocols) and three series of thoracic radiotherapy delivering a total dose of 45, 55, and 65 Gy in each consecutive protocol. Radiotherapy was started after the second course of chemotherapy. A 1-week gap was respected between each course of chemotherapy and each series of radiotherapy. Seventy percent of patients were in complete remission at the end of the induction treatment. The actuarial 5-year local control was 60% and the 5-year overall survival was 18%. Sixty percent of patients developed distant metastases. The death rate unrelated to cancer was 10%. These results show that alternating radiotherapy and chemotherapy schedules are reproducible, and provide a consistent long-term local control and a long-term survival rate exceeding 15% in limited disease.