5554 Background: Altered fractionation radiation therapy has been thought to improve the local control and survival of the patients with head and neck cancer. Since 1996, we have been conducting a clinical trial of hyperfractionated radiation therapy (HFRT) for the treatment of squamous cell carcinoma of the head and neck (SCCHN). Methods: Between 1996 and 2002 88 cases with SCCHN were treated and analyzed. Average age was 64.7 (39–91), M/F=77/11. Primary site: Larynx 34 cases, hypopharynx 27 cases, oropharynx 17 cases, oral cavity 5 cases, nasopharynx 4 cases, and maxillary sinus 2 cases. Stage I/II/III/IV(M0) = 11/32/15/31. Radiotherapy was administered with 4MVXrays. Fraction dose was 1.2Gy twice a day more than 6 hours apart, to the average total dose of 71.7Gy (range 60∼81.6Gy). Chemotherapy was combined in 22 cases. Median follow-up period was 37 months. Results: Five-year overall survival rate (OS) and local control rate (LC) of overall cases were 67.6% and 73.8%, respectively. OS and LC of stage I-II and III-IV were, 82.7%, 95.2%, and 54.5%, 53.5%, respectively. As for larynx, OS and LC of overall, stage I-II, and stage III-IV were, 91.2%, 84.2%, 100%, 93.8%, and 50% (2y), 67% (1y), respectively. As for oropharynx, OS and LC of overall, stage I-II, and stage III-IV were, 71.1%, 83.9%, 100% (2y), 100% (2y), and 73.8%, 80%, respectively. As for hypopharynx, OS and LC of overall, stage I-II, and stage III-IV were, 49.9%, 65.3%, 53.6%, 100%, and 48.2%, 42.9%, respectively. Disease-specific survival of stage I-II hypopharyngeal cancer was 100%. Acute toxicities of grade 3 or greater were observed in 17 cases (19%). No severe late toxicity has been observed. Conclusions: HFRT for SCCHN was promising not only for stage III and IV(advanced) cases but also for stage I and II (early) cases. No significant financial relationships to disclose.