Pulmonary hamartoma has been considered as rare disease, which consists of lung tumor less than 1 %. Originally described by Albrecht in 1904, hamartoma is tumor like malformation-abnormal mixing of the normal components of organ-and is applied also to tumor found in many organs other than the lung. Lately, the major conclusions are that pulmonary hamartoma is neoplastic rather than developmental error in origin. Because pulmonary hamartoma frequently mimics lung cancer, especially in cancer-risk age groups, its clinical significance is great. Recently, we experienced 1 cases of endobronchial hamartoma which located at the right main stem bronchus. The patient was a 54 year old male who was admitted due to symptoms of fever 4 chilliness and dyspnea. Radiologic studies such as chest x-ray, chest tomogram and chest C-T scan revealed that the nearly total haziness of the right lung was caused by endobronchial tumor. The mass was considered as a benign by bronchoscopic exam, so we removed it surgically by tracheobronchotomy without pulmonary resection. Postoperative chest x-ray revealed satisfactory reexpansion of previous collapsed right lung. The patient discharged uneventfully.