From 1964 to 1990, 134 patients were treated at the University of Florida with continuous-course external beam irradiation, alone or followed by a planned neck dissection, for T1 (n = 17), T2 (n = 47), T3 (n = 49), or T4 (n = 21) carcinoma of the base of tongue. The 5-year rate of local control was 90% for stage T1, 92% for T2, 73% for T3, and 35% for T4. Probability of control above the clavicles at 5 years according to modified American Joint Committee on Cancer (AJCC) stage was 100% for stages I and II, 75% for stage III, 84% for stage IVa, and 52% for stage IVb. Probability of relapse-free survival at 5 years was 100% for stages I and II, 68% for stage III, 81% for stage IVa, and 37% for stage IVb. Severe complications occurred in 2% of patients. Compared with surgical resection of the primary tumor, external beam radiotherapy results in similar rates of local control and survival with a lower risk of severe complications.