Forty consecutive patients with small cell carcinoma of the lung were treated with chemotherapy, radiotherapy or both. Of 34 patients treated with chemotherapy, 24 were treated with combination chemotherapy, containing cyclophosphamide vincristine methotrexate and procarbazine, concurrent with small dose radiation therapy (500cGy/5 fraction) as a chemosensitizer (COMPrt). The response rate to this regimen was 81% (29% complete) and the 2 year survival rate was 28.6%. These results have been superior to other regimens and the toxicity was not see to be any higher. After completion of COMPrt regimen, 10 patients were treated with intrathoracic radiation therapy (average dose 3000cGy) and 3 received surgical treatment. Radiation therapy improved the 2-year survival rate (42.2%) when compared with those patients who received no radiation therapy (18.2%). Three patients received surgical treatment were considered to be disease-free for 23, 17, and 9 months respectively, after induction of chemotherapy.