Epidermoid and dermoid cysts in the oral cavity are relatively uncommon lesions of developmental origin. They often remain asymptomatic for years until they grow enough to interfere with speech, deglutition and less often with breathing which can pose a critical risk to the airway and require immediate surgery.A case of an epidermoid cyst of the floor of the mouth affecting a 37-year-old man is presented; this lesion was surgically enucleated with an intraoral approach. Patient did well postoperatively and there was no evidence of recurrence up to 2 years of follow up.Floor of the mouth is a challenging site for the diagnosis of a broad variety of lesions which the surgeon should be aware. Depending on the anatomical relation to the muscles of the floor of the mouth dermoid cysts are classified as supramylohyoid or inframylohyoid, and they will both have different clinical and radiological features. This article also includes literature review about the etiopathological, clinical, radiological and histological features, the differential diagnosis and its treatment. Key words:Epidermoid cyst, dermoid cyst, floor of mouth.