Eighty-five patients with small cell lung cancer (limited disease = LD in 39, extensive disease = ED in 46) received the combination of cyclophosphamide, methotrexate, vincristine and CCNU, and mediastinal radiotherapy given simultaneously after the third course of chemotherapy. The duration of treatment was approximately 12 months. A complete response was obtained in 41% of LD and in 15% of ED patients, and a partial response in 38 and 22%, respectively. Median survival was 55 weeks for LD and 37 weeks for ED patients. Two patients (5%) with LD have survived free of disease more than 3 years since their diagnosis.