An afterloading endobronchial irradiation (EBRT) technique using Iridium-192 (Ir-192), was piloted for malignant airway obstruction. Under bronchoscopic guidance, a catheter is threaded distal to the lesion. Orthogonal radiographs and computerized tomographic (CT) scans are obtained for dosimetry. Forty implants in 38 patients have been performed. Thirty-two patients had lung cancer; 23 had received prior irradiation and eight had prior chemotherapy. Eight patients underwent pre-endobronchial irradiation laser excision. Median implant duration was 50.5 hr; median dose at 1 and 2 cm from source center was 50 and 20 Gy, respectively. The procedure was well tolerated with four long-term complications (10.5%). Twelve of 38 patients are currently alive with a median survival of 5+ months and a range of 1 to 21+ months. Changes in performance status (PS), symptom resolution, radiographic demonstration of re-aeration of atelectatic lung, changes in pulmonary function (PFT), and post-endobronchial irradiation bronchoscopy were used to assess response. Seventy percent of the patients' remaining life was rendered symptom-free or improved. A 70% radiographic response was noted. Fourteen patients underwent post-endobronchial irradiation bronchoscopy with 12 complete responses. Endobronchial irradiation, therefore, appears to be a safe, effective technique to palliate malignant airway obstruction.