After Roser, 1859, first described dermoid cysts on the floor of the mouth as epidermoid tumors. Dermoid cysts on the floor of the mouth are occasional findings in the oral cavity. These lesions are thought to be developed from traumatic implantation of epithelial tissue of inclusion of the ectodermal components within the mesoderm at the time of fissural union, but the exact nature of the production of the rests is not clear. Cysts of the floor of the mouth has been classified as epidermoid, dermoid and teratomatous cyst. Dermoid cysts are more common in young adults in the secound or third decades and no sex predilection. Recently we experienced 3 cases of huge dermoid cysts from the mouth floor and submental space and are going to report dealing with diagnostic and therapeutic problem.