PURPOSE: In supraglottic cancer, radiation therapy is used to preserve the laryngeal function but combined surgery and radiation therapy is required in advanced stage. The authors present the results of radiation therapy alone and combined surgery plus postoperative radiation therapy for supraglottic cancer. METHODS AND MATERIALS: A retrospective analysis was done for 43 patients with squamous cell carcinoma of the supraglottic larynx who were treated from February 1982 to December 1991, in the Department of Radiation Oncology, Korea University Hospital. Patient distribution according to the AJCC staging system was as follows; I, 3(7.0%); II, 7(16.3%); III, 17(39.5%); IV, 16(37.2%). Patients' age ranged from 30 to 72 years(median 62). Follow up durations were from 21 to 137 months(median 27). Seventeen patients(39.5%) were treated by radiation therapy alone with radiation doses of 6840-7380 cGy and 26 patients(60.5%) were treated with surgery plus postoperative irradiation with doses of 5820-6660 cGy. RESULTS: Overall five-year survival rate for all stage was 51.8%, with 100% for Stage I and II, 47.3% for Stage III, and 29.2% for Stage IV. The difference of the survival rate by stage was statistically significant(p=0.0152). Five-year survival rates were 100% for locally confined tumor in the supraglottic larynx, 37.5% for transglottic extension, 26.7% for hypopharynx extension, and only two of 5 patients with both transglottic and hypopharynx extension were alive(p=0.0033). Five-year survival rates by neck node status were as follows: 55.0% for N0, 64.3% for N1, 50.0% for N2, and all 2 of N3 were died of disease. Overall survival rate for radiation therapy alone group was 42.8% and it was 56.7% for surgery plus postoperative radiation therapy group with no statistically significant difference(p=0.5215). In Stage I and II, all patients survived. In Stage III and IV, 5-year survival rate for radiation therapy alone group was 28.5% and 43.4% for surgery plus postoperative irradiation group(p=0.5103). Local control rate was 58.8%(10/17) for radiation therapy alone group and 73.1%(19/26) for surgery plus postoperative irradiation group. Three patients from surgery plus postoperative radiation therapy group developed distant metastasis in lungs. CONCLUSION: Treatment results of radiation therapy alone was excellent in early stage supraglottic cancer. In advanced stage, even the difference was statistically not significant, the result of postoperative radiation therapy group was superior compared with radiation therapy alone group. Since 1992, concomitant chemoradiotherapy with hyperfractionated radiotherapy is being used to improve the result of the treatment and preserve the laryngeal function in advanced stage supraglottic cancer.