Most carcinomas of the oral tongue and floor of the mouth are presently treated surgically, often combined with pre- or postopervative irradiation. The treatment plan is mainly determined by the primary site and the local and regional extension, desirable are general rules on the basis of the TNM classification. The indications and principles of the most important operative procedures are discussed: Local excision, partial glossectomy, excision of the floor of the mouth with marginal mandibulectomy, composite resection. Operations for removal of the primary and radical neck dissection with preservation of the mandible (e.g. the pull-through procedure) are rarely advised. A radical neck dissection is indicated in each carcinoma of the oral tongue or floor of the mouth with palpable lymph nodes. If no nodes are palpable, an elective neck dissection is advised in view of the high frequency of clinically occult lymph node metastases (between 23 and 43%). Reconstructive measures following radical tongue and floor of the mouth operations are required for regaining a motility of the remaining tongue, for reconstruction of the floor of the mouth and for replacement of the mandible.