Adenoid Cystic Carcinoma (Cylindroma) is a rare malignant tumor arising from glandular structure, especially in minor salivary tissues, but can be shown in nasal cavity and paranasal sinuses, tonsil, larynx and trachea, ear canal and lacrimal glands. Distant metastasis is also seen in lung, brain, bone and liver. The authors experienced 2 cases of Adenoid Cystic Carcinoma arising from the right maxillary sinuse in a 40 year old male who had mass on the cheek, and from the nasal septum in a 51 year old woman. The tumor mass was removed surgically by CL-Op and external rhinotomy respectively, confirmed as Adenoid Cystic Carcinoma by the histologic examination. Post-operative radiation therapy was done.