Pulmonary hamartochondromas are tumor-like malformations, often presenting as asymptomatic, noncharacteristic masses that sometimes cannot be differentiated from lung carcinomas and metastases, preoperatively. Eleven patients (6 females and 5 males) with hamartochondroma of the lung were treated at this Institute over a 10 years period. Definitive diagnosis was established at thoracotomy, and treatment of choice was wedge resection. Two patients had pleural postoperative complications while the others made an excellent recovery. All patients are still alive (median survival: 56 months) and no recurrences occurred. Several studies showed that CT and transthoracic needle-aspiration biopsy are reliable methods to achieve the diagnosis in such benign lesions and their use allows a conservative approach. Since none of our cases could be diagnosed with certainty by the above procedures we always performed diagnostic and therapeutic thoracotomy with excellent results.