Seventy patients with small-cell lung carcinoma limited to the thorax +/- ipsilateral supraclavicular lymph nodes were randomized to either of two study arms: 33 patients received radiation therapy (RT) alone consisting of 4500 rads in 5-6 weeks to primary tumor and regional lymph nodes, and 3500 rads in 2 1/2 weeks to brain as prophylaxis; 37 patients received, in addition to the RT above, chemotherapy (CT) with cyclophosphamide (500 mg/m2), Adriamycin (50 mg/m2), and DTIC (250 mg/m2) every 3 weeks given in two cycles before RT and seven cycles post-RT. Patients receiving RT alone who showed recurrence were crossed over to receive CT as above. Of 23 patients receiving RT alone who were evaluable 17 or 74% were responders; seven of these responses were complete (30%). On the RT and CT arm, of 24 evaluable cases, the response rate was 75%, of which 12 (50%) were complete. The median duration of disease-free survival of patients receiving RT + CT was 27 weeks, which ws superior to that of patients receiving RT alone (9.9 weeks, p = 0.019). The median survival of responders was essentially the same on both treatment arms; RT + CT, 47.7 weeks vs. RT alone, 50 weeks (p = N.S.).