The authors have observed a case of the nasoalveolar cyst originated in the left nasolabial region of a 25 years old Korean female admitted the Taegu Presbyterian Hospital on Jan. 28, 1972. She complained of a painless large mass in the left nasolabial region, which had been progressively increasing in size for 6 months. At last there presented obstruction of left nostril due to above growing mass. The result of surgical excision was satisfactory. There has been much discussion about the pathogenesis of the nasoalveolar cyst. And then the facial cleft theory of Klestadt is adhered at present and seems the most plausible hypothesis. It demands differential diagnosis with several types of fissural cyst of same etiology and several cystic lesions of ther etiology which present themselves in the floor of the nose.