Pulmonary hamartomas are common benign lung tumors. Most cases are parenchymal chondromatous hamartomas, whereas endobronchial lipomatous hamartomas are rarely encountered. A 78-year-old man was referred for left superior subsegmental atelectasis due to obstruction by an endobronchial tumor that was found incidentally on chest computed tomography for the postoperative follow-up of colon cancer. Bronchoscopy showed a polypoid tumor in the orifice of the left upper segmental bronchus. Lipoma was diagnosed by a bronchoscopic biopsy. We performed a segmentectomy of the upper division of the left lung because the tumor was presumed to be located peripherally to the left B3 segmental bronchus. A histopathological examination revealed that the tumor was an endobronchial lipomatous hamartoma that extended to the pulmonary parenchyma beyond the bronchial wall.