Epidermoid cyst of the mouth and submandibular area develops from a misplaced fetal inclusion. Dysontogenetic cyst can be classified into epidermoid, dermoid and teratoid cyst. Complete excision of this lesion with adequate exposure is necessary for prevention of recurrence, although this tumor is benign. Recently. The authors have experienced a epidermoid cyst of the mouth floor. So, we report the case with review of literatures.