The palliative treatment of lung atelectasis can significantly improve the quality of life in the patients who are unsuitable for cure. The authors present a new transcutaneous radiotherapy technique for treating this complication of lung cancer. After conventional and CT localization, a treatment is scheduled featuring a small (3-5 cm wide and 4-6 cm long) single 180 degrees arc beam giving 14 Gy to the 90% isodose line in two daily fractions. The treatment is repeated 3 weeks later (dosage: 28 Gy). The mean dosage to the ICRU reference point was 34 Gy; the min., max. and mean dosages to the planning target volume were 31, and 35 Gy, respectively, in 4 fractions over a 3-week period. Lesions were localized best by positioning the distal end of a fiberoscope close to the tumor and by checking its position under fluoroscopic guidance, on two orthogonal projections, immediately after every treatment session. Nine patients with histologically-proven non-small cell lung cancer were treated. They relapsed after surgery and/or full-course radiotherapy. Lung reventilation, demonstrated with fiberbronchoscopy and on chest films, was observed in 8/9 patients, in 1 of them lasting for about 40 days. In the extant 7/8 cases, it lasted longer (range: 60-180 days). Of the latter patients, 5 are alive and 2 died 60 and 86 days after treatment, with no atelectasis. The treatment was very well tolerated and severe symptoms were relieved with no complications.