The hamartoma is the most common benign tumor of the lung, but the incidence is very low. Most of hamartomas are revealed accidentally as coin lesion of routine chest X-ray because of no symptoms usually. The differential diagnosis should include tuberculoma, bronchogenic carcinoma, and other forms of tumor. Definitive diagnosis usually is established at exploratory thoracotomy. In this report, we present one case of a 42-year-old female having hamartoma of the left lower lobe of the lung that removed successfully and confirmed histopathologically. Her postoperative course was uneventful. She was discharged in good condition.