Development of congenital branchial cysts is due to persistance of branchial remnant, and is not extremely rare. We report three cases of branchial cysts who were admitted at the department of otolaryngology, SNUH, recently. The patients were a 20 year-old, and 22 year-old male, and 19 year-old female, who complained progressively increasing mass in lateral neck. They were all treated with complete excision with very satisfactory results. The final diagnoses were confirmed by histopathological study.