Dermoid cyst on the floor of the mouth is known as unusual disease and of congenital origin as a dysontogenic. Dermoid cyst are more common in 3rd and 4th decade and no sex predilection. The author experienced 3 cases of dermoid cyst on the floor of the mouth for recent several years. Surgically the cysts were completely removed with blunt dissection under general anesthesia and histopathologically the final diagnosis was confirmed as dermoid cyst.