Forty-three patients with limited-disease, inoperable non-small cell lung cancer received two intravenous courses of cyclophosphamide, Adriamycin, and cisplatin (CAP) chemotherapy over a 6-week period. This was followed by 5 weeks of combined chemoradiotherapy (CCRT) consisting of low weekly doses of CAP for 5 weeks plus 50 Gy continuous X ray therapy (XRT) to the primary tumor site. Chemotherapy was continued until disease progression occurred or until the total dose of Adriamycin reached 450 mg/m2, whichever came first. CCRT improved the response rate [complete response (CR) plus partial responses (PR)] from 25% after two courses of CAP alone to 65% after CCRT. Previous response to two courses of CAP influences response subsequent to CAP plus XRT. A pretherapy weight loss of 6% or greater had a significant adverse effect on both response and survival time. The median survival time for all patients was 50 weeks; patients whose disease responded to treatment survived significantly longer than patients with nonresponding disease. The median time until disease progression was 37 weeks. Twenty-seven patients relapsed. The first sites of relapse were local in 30% of the patients, distant in 56% of them, and both local and distant in 15%. Severe esophagitis occurred in 30% of the patients and was dose-limiting. The administration of CCRT resulted in an improved response rate compared with the rates reported in previous studies of chemotherapy or radiotherapy alone. Further improvement of the CCRT program is needed to increase long-term survival time and to decrease esophageal toxicity.