PURPOSE Resectability, local control, and survival were evaluated in advanced stage nonsmall cell lung cancer treated with simultaneous chemoradiation therapy delivered in an accelerated, interrupted twice-a-day schedule. METHODS AND MATERIALS Forty-seven consecutive patients with Stage IIIA or IIIB nonsmall cell lung cancer, consenting to participation in the study, received cisplatin, 30 mg/m2 for 3 days, etoposid, 80 mg/m2 for 3 days, and 5-fluorouracil, 900 mg/m2 for 4 days. Radiation therapy consisted of 2 Gy given twice a day for 5 days. Two weeks rest was planned between cycles. Patients were evaluated for resectability after the second cycle. Any patient with unresectable tumor received a third cycle of treatment. RESULTS Forty-seven patients were evaluable for acute toxicity: eighteen (38%) required an extended rest period for esophagitis or low blood count; 3 (6%) had sepsis, of whom 1 (2%) expired. Three patients (6%) had multiple blood transfusions for low hemoglobin. Median follow-up is 23.6 months, with a range of 10-49 months. Nine patients (19%) failed locally; 15 (32%) had local and distant failure; 7 (15%) failed only at distant sites. Twelve patients (25.5%) are alive with no evidence of disease; 4 patients were lost to follow-up with disease. The 2-year actuarial survival is 49%, and the 4-year is 28.2%. CONCLUSION Simultaneous chemoradiation is well tolerated with acceptable toxicity. The overall 2- and 4-year actuarial survival is somewhat better than that reported in the literature. Resectability in Stage IIIB patients was not increased with this regimen nor was any surgical specimen free of cancer. The 47% distant failure rate is not different from those reported by others.