Stenosis of the larynx and/or trachea presents perplexing problems. No one technique has proved totally satisfactory in the management of all varieties of stenosis. Recent reports have described the successful use of the CO2 laser in the endoscopic management of stenosis of the larynx and trachea. Failures of this technique need emphasis to assure appropriate selection of therapeutic method. Retrospectively, 49 cases of laryngeal stenosis, 6 cases of tracheal stenosis and 5 cases of combined laryngeal and tracheal stenosis were studied (total 60 patients) following treatment at the Boston University Affiliated Hospitals. Follow-up ranged from 1 to 8 years. Multiple procedures were required in 35 laryngeal patients. Of the laryngeal patients 39 were successfully managed (average number of procedures in successful cases 2.18). Of 11 tracheal patients with combined laryngeal and tracheal procedures, 3 were successfully managed (average number of procedures in successful cases 6). Failures in laryngeal stenosis included four patients in whom an adequate airway was not established though voice was present while maintaining tracheostomies. Thirteen patients failing endoscopic management required open surgery with good result. Factors associated with poor result or failure include circumferential scarring with cicatricial contracture, scarring wider than 1 cm in vertical dimension, tracheomalacia and loss of cartilage, previous history of severe bacterial infection associated with tracheostomy, and posterior laryngeal inlet scarring with arytenoid fixation. In these circumstances, multiple procedures, more extensive alternative open surgical techniques, or maintenance of tracheostomy were necessary. In successful cases only three or fewer procedures on average were required. The factors associated with failure or success of endoscopic methods in the management of laryngotracheal stenosis, including use of the CO2 laser and soft Silastic stents, are analyzed.