We evaluated the treatment outcome for 5-field 3-dimensional conformal radiation therapy (3D-CRT) in 46 consecutive patients with unresectable, nonmetastatic non-small-cell lung cancer treated from 1993-2001. Four percent of the patients had stage I tumors, 6% had stage II, 44% had stage IIIA, and 46% had stage IIIB tumors. The median radiation therapy (RT) dose to the gross tumor volume with a median of 467.5 cc (range, 75.0-3073.0 cc) was 6120 cGy (range, 3000-6840 cGy). Thirty-one of 46 patients (67.4%) received combined chemoradiotherapy. Mean follow-up was 13.2 months (range, 3-159 months). Survival for stage III patients was 48.7% +/-9.1% at 1 year and 25.0% +/-8.4% at 2 years, with a median survival of 12.0 months+/-4.4 months. The local control rate for stage III patients was 66.8%+/- 9.4% at 1 year and 28.5%+/- 10.4% at 2 years. Patients who received chemotherapy had better survival (P = 0.0533) and local control (P = 0.0984) compared with patients receiving RT alone. Esophageal toxicity >or= grade 3 was significantly greater in combined chemoradiotherapy patients (29% early, 13% late) compared to the patients receiving RT alone (0% early and late). Pulmonary toxicity (early and late) was limited to grades 1/2 in 24% of patients and early grade 3 in 2% of patients. Chemotherapy appears to improve survival and local control when added to 3D-CRT in this series. The addition of concurrent chemotherapy to RT significantly increased esophageal toxicity (within acceptable levels) and did not effect pulmonary toxicity in this series.