431 patients with tumor of head and neck were treated by radiation at Yonsei Cancer Center. 145 patients of 431 patients were available for follow-up examination. 145 cases were reviewed in respect of method of radiation therapy, incidence of diseases, sex, age histologic type and effect of radiation therapy in the view of prognosis. 1. The most common lesion among the tumor of head and neck was laryngeal cancer 38.6%(56/145) and next was maxillary cancer 20.7%(30/145), nasopharyngeal cancer 13.8%(20/145), tongue cancer 9.6%(14/145), tonsillar tumor 6.9%(10/145), parotid gland tumor 5.5%(18/145) and the last was thyroid gland tumor 4.8%(7/145). 2. Sex incidence shows more common in male in layngeal, maxillary, nasopharynx, tongue, tonsil, and parotid gland tumor, however more common in female in thyroid cancer. 3. The peak age incidence was 5th and 6th decade in all head and neck tumor. 4. In histologic type, epidermoid cell cancer was the most common type of larynx, maxillary nasopharynx, tongue and tonsillar lesion and mucoepidermoid cancer is most common in the parotid gland tumor. 5. Average survival months after radiation therapy was 22.4 months in laryngeal cancer, 18.9 months in maxillary cancer, 106 months in nasopharyngeal tumor, 20.5 months in tongue cancer, 21.4 months in tonsillar cancer, 26 months in parotid gland tumor and 13.6 months in the thyroid gland tumor. 6. Postradiation complications were minor degree of dry mouth, taste loss and skin discoloration, but major complication such as necrosis of soft tissue and bone or transverse myelitis of spinal cord was not developed.