The bronchogenic cysts result from an abnormal budding or branching of the tracheo-bronchial tree from the primitive foregut. Bronchogenic cysts may be pulmonary or mediastinal. The most common location for a mediastinal bronchogenic cyst is in relation to the carina. They are usually solitary. They usually are thin walled and contain fluid that is most often clear. The cyst is lined by ciliated columnar epithelium. The bronchogenic cyst i~ usually asymptomatic. They can cause pressure symptoms. When they become infected, symptoms do occur. We report 3 cases of bronchogenic cysts experienced at the Department of Thoracic and Cardiovascular Surgery, Kyungpook National University Hospital. Case I, a man of 20 year-old, had a cyst at the site between aortic arch and left pulmonary artery. He complained cough and dyspnea. The cyst wasn`t communicated with tracheobronchial tree. Case II was 55-year-old male who had had hemoptysis. A huge cyst was located within the lower lobe of left lung and removed by pulmonary lobectomy. There were not any symptoms in Case III that was 6-year old girl. That cyst was located just next to the right main bronchus. [KTCS 1981;3:210-214]