Bronchogenic cysts, though known as a relatively common malformation of the mediastinum, were rarely discussed in Korean literatures. Since the surgical removal of asymptomatic lesions was adopted as the reasonable therapeutic principle, the incidence of bronchogenic cysts were found to be higher than previously expected. Two cases of bronchogenic cysts operated on in The Dept. of Thoracic Surgery, Korea University Woo Sok Hospital were reported and related literatures were reviewed. Case 1. 5 year old boy with chief complaints of bulging cystic mass on left supraclavicular region during straining or coughing since his age of 2 was admitted, and cystogram with Lipiodol revealed hen-egg sized mass in the left antero-superior mediastinum without any communication with bronchus or esophagus. Cyst was successfully removed under general anesthesia thru left supraclavicular incision, and pathological examination of the cyst revealed thin cystic wall lined with stratified columnar epithelium and it`s content was milky white mucoid fluid devoid of any bacterial growth. Case 2. 15 year old school girl has been noted slowly growing walnut-sized mass on anterolateral side of the neck for 4 months without any subjective symptom except cosmetic problem... Mass was aspirated to find milky white mucoid fluid in some loculation and yellowish turbid fluid in other part due to chronic infection. Cystic tumor was removed under local anesthesia, which was loculated in between the trachea and esophagus without any communication, and pathological diagnosis of the cyst was bronchogenic cyst with columnar epithelial cell lining with moderate chronic inflammatory cell infiltrations. Postoperative conditions of the two cases were all excellent with normal life.[KTCS 1974;1:9- 12]