Benign pulmonary tumors are rare and represent only less than 1% of pulmonary tumors, of these, hamartomas are most common. Among them, Endobronchially located hamartomas are rare and account for only for 1.4% of all pulmonary hamartomas. The improving techniques of therapeutic bronchoscopy have been replacing conventional surgery for resecting endobronchial benign tumor, although there are some limitations for performing, such as completely obstructing large-sized tumor. We report here a case of giant endobronchial hamartoma inducing total atelectasis of a lung, which was successfully treated with electrosurgical snare via fi exible bronchoscopy. A 50-yearold male, presented with dyspnea, cough and sputum for 3 weeks. Chest radiograph revealed total atelectasis of the left lung. Chest computed tomography (CT) scan of the patient showed a mass lesion completely obliterating left main bronchus. An initial bronchoscopy revealed a large mass totally obstructing left main bronchus, and bronchoscopic biopsy was confi rmed as endobronchially located hamartoma. Three sequential therapeutic (fi exible) bronchoscopy were performed under the conscious sedation. An elongated tight mass was split and removed by piecemeal with electrosurgical snare-cutting method, and we discovered that the root of the mass was from the superior lingular segment. We removed the mass until the lingular bronchial passage was completely open. After endoscopic treatment, the left lung total atelectasis was improved little by little through several weeks. 3 months later, chest CT revealed that the left lung except lingula was completely recovered from atelectasis. One year after treatment, He is doing well without any complications. fiexible bronchoscopy with electrosurgical snare under conscious sedation could be a useful option for completely obstructing large-sized benign endobronchial tumors without signifi cant risk.