Introduction: A phase-II study was planned to test the effect of external beam radiotherapy in combination with endobronchial brachytherapy on the local control and survival of stage-III non-small cell lung cancer patients. Materials and methods: Thirty patients with stage-III non-small cell lung cancer have been treated with 60 Gy external beam radiotherapy and 3 x 5 Gy HDR endobronchial brachytherapy to control tumor and to prolong survival. Results: Therapy regimen was found to be very effective for the palliation of major symptoms, palliation rates were 42.8% for cough, 95.2% for hemoptysis, 88.2% for chest pain and 80.0% for dyspnea. There was a 76.7% tumor response (53.3% complete, 23.3% partial) verified by chest CT scans and bronchoscopy. However, median locoregional disease free survival was 9 +/- 4 months (95% Cl: 1-17) and it was only 9.6% at 5 years. Major side effects were radiation bronchitis (70.0%), esophagitis (6.6%) in the acute period and bronchial fibrosis (25%), esophagial fibrosis (12.5%) and fatal hemoptysis (10.5%) in the late period. Median survival was 11 +/- 4 months (95% CI: 4-18),and 5-year actuarial survival was 10%. Locoregional disease free survival (P = 0.008) and the overall survival was longer (P < 0.001) in the patients younger than 60, survival was also improved in the patients with complete response (P = 0.019). There were no major complications during catheterisation; early side effects were quite tolerable but severe late complications were around 10%. Conclusions: It is concluded that endobronchial brachytherapy in combination with external irradiation provides a good rate of response, however does not eradicate locoregional disease and does not prolong survival except for some subgroups such as younger patients. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.