PURPOSE: There has been no definitive randomized study to identify the optimal therapeutic regimen for treating squamous cell carcinoma of tonsil. The purpose of this study was to retrospectively evaluate the treatment outcome according to various combinations of surgery, radiation therapy and chemotherapy. MATERIALS AND METHODS: Fifty-six patients with tonsillar carcinoma, who were treated at Seoul National University Hospital from March 1985 to August 2001, were the subjects of this study. Twenty-one patients received surgery followed by radiation therapy (SRT), 16 patients underwent radiation therapy alone (RT), and 19 patients received neoadjuvant chemotherapy and radiation therapy (CRT). The median radiation dose was 66.6 Gy for the SRT group and 70.2 Gy for the RT and CRT groups. Surgery comprised extended tonsillectomy and modified radical neck dissection of the involved neck. Cisplatin and 5-fluorouracil were used every three weeks for 3 cycles in the SRT group. The median follow-up was 73.2 months. RESULTS: The distribution of T-stage was 4 cases of T1, 14 cases of T2, 1 case of T3 and 2 cases of T4 staging in the SRT group, 2 cases of T1, 6 cases of T2, 5 cases of T3 and 3 cases of T4 staging in the RT group and 0 cases of T1, 7 cases of T2, 9 cases of T3 and 3 cases of T4 staging in the CRT group. The distribution of N-stage was 5 cases of N0, 2 cases of N1, 13 cases of N2 and 1 case of N3 staging in the SRT group, 6 cases of N0, 5 cases of N1, 5 cases of N2 and 0 cases of N3 staging in the RT group, and 2 cases of N0, and 7 cases of N1, 9 cases of N2 and 1 case of N3 staging in the CRT group. The five-year overall survival rate (OSR) for all patients was 78%. The five-year OSR was 80% for the SRT group, 71% for the RT group, and 80% for the CRT group (p=ns). The five-year disease-free survival rate was 93% for the CRT group and 71% for the RT group (p=0.017). Four patients developed local failure and one patient failed at a regional site in the RT group, and one patient failed at a primary site in the CRT group. The five-year DFS was 84% for patients who had undergone neck dissection and 76% for patients who had not undergone neck dissection (p=ns). Treatment-related complications of grade 3 or 4 occurred in 15 patients, and the incidence of complication was not different between each of the treatment methods. CONCLUSION: Although the patients with more advanced T stage were included in the RT and CRT groups, the OSR was not statistically different according to the treatment methods. In the radical radiation therapy group, the addition of neoadjuvant chemotherapy showed an improvement in the disease-free survival. Because of the retrospective nature of our study and the small number of patients, this study cannot draw any definite conclusions, but it suggests that radiation therapy with chemotherapy can be a good alternative option for squamous cell carcinoma of tonsil. Controlled randomized study is necessary to confirm this hypothesis.