Dermoid cyst of the floor of mouth is infrequent. This cyst has been classified as epidermoid, dermoid and teratoid cyst. Dermoid cyst is more common in young adults and no sex predilection and has generally been present for months to years before progressive enlargement causes interference with the mobility of the tongue and disturbance of articulation and mastication. The authors have recently experienced dermoid cyst of the floor of mouth which was confirmed histopathologically.