Endobronchial electrocautery was successfully used to treat three patients with major airway obstruction resulting from bronchogenic carcinoma and to establish a diagnosis in a fourth. Electrocautery was applied through fiberoptic bronchoscopes. In two cases, a wire snare was used to remove polypoid lesions and in two others, probes were used to ablate tumor tissue. As a result of high inspired oxygen concentration in one patient, a tracheal fire occurred without injury to the patient. Electrocautery is an available economical tool which has potential value in the diagnosis and therapy of endobronchial obstructing airway lesions.