Choanal atresia is the congenital failure of one or both posterior nasal apertures to communicate with the nasopharynx, and 20 to 50% of these patients are accompanied with other congenital defects. Because bilateral congenital choanal atresia in newborn who is absolute nasal breather carries a high risk of brain damage due to hypoxia and aspiration, proper treatment such as early diagnosis is preferably. Primarily in the delivery room, temporary measures such as inserting an oral airway or a gavage tube are usually sufficient to establish satisfactory respiration. Careful observation is essential in the nursery during the period of local and general diagnostic evaluation to prevent repeated spells of apnea. However, since unilateral choanal ateresia is usually recognized in childhood or adult, and it needed observation policy, and elective & safe operation technique with minimal morbidity for predictable long term results. The authors have experienced two cases of unilateral congenital choanal atresia in neonate. One patients has shown good prognosis by conservation management, but the other was deceased with multiple congenital defects.