The anterior arch of the mandible is essential for satisfactory oral function and appearance. It can be preserved in surgical treatment of advanced cancers of the floor of the mouth by partial thickness resection. Surgery and radiation are approximately equally effective in the control of advanced (T3) primary lesions. A treatment plan is proposed which employs a combination of nondisabling surgical resection followed by immediate postoperative radiation. Of 19 patients with T2, T3, and T4 lesions treated and followed 1 year or more, 11 were free of cancer, including six who had positive lymph nodes. Of those dying of cancer, only one had local recurrence, while recurrence in the neck occurred in four. This report further strengthens the need for postsurgical radiation in certain situations.