Between April 1980 and November 1990, we treated 212 cases of airway lesion using an Nd-YAG laser via the fiberoptic bronchoscope. The Nd-YAG laser power output was usually 40 W (20-60 W) delivered in 2 sec. shots. The cases consisted of 98 primary lung cancer, 12 primary tracheal cancer, 53 metastatic airway lesion, 7 benign tumor, and 42 cicatricial and granulomatous lesions. The therapeutic effects of Nd-YAG laser treatment were evaluated based on alleviation of dyspnea, widening of airway, and curative vaporization for therapeutic purposes. Effectiveness was observed in 180 of a total of 212 cases (84.9%). Out of 75 emergency cases in which a lifesaving procedure was performed to widen the airway, effective results were obtained in 70 (93.3%) with dramatic improvement in condition. It was also effective in 90 of 109 cases (82.6%) in which the procedure was performed for staged (palliative) widening of airway. In 55 cases of advanced lung cancer (Stage III or IV, mainly non-small cell cancer) in which palliative widening procedure was performed, one year survival was 44%. In 13 of 18 cases (72.2%) in which the procedure was performed for curative vaporization of invasive cancer, successful results were obtained. In 7 cases of benign tumor in which vaporization was performed as a radical curative procedure, no recurrence was observed in any cases. In 53 cases of metastatic airway lesion, effective results were obtained 48 (90.6%). The primary lesions of these cases consisted of 14 cases of esophageal cancer, 9 cases of lung cancer, 7 cases of colo-rectal cancer, 7 cases of thyroid cancer, and 16 others.(ABSTRACT TRUNCATED AT 250 WORDS)