Forty-eight patients with T1 or T2 epidermoid carcinomas of the base of tongue were treated at the Henri Mondor Hospital between 1971 and 1981. Forty-one patients received moderate dose 60Co external beam irradiation (mean: 48.6 Gy) to the primary tumor and regional nodes, followed by an interstitial iridium 192 implant to the primary tumor (mean: 32 Gy). This completed the treatment for the 30 node negative patients, but those with clinically positive nodes were managed by either an additional electron beam boost to the involved nodes or a neck dissection. Seven tumors were treated exclusively by implantation to the base of tongue (mean: 63 Gy). Five-year crude disease-free survival is 50% with 35% of patients dying of recurrent disease. Definitive local control for T1 lesions is 85% (11/13) and for T2 is 71% (25/35). A dose response effect was observed with local control of 79% (26/33) obtained with a combined dose greater than or equal to 75 Gy, but only 50% (4/8) for less than or equal to 70 Gy. For N0 patients definitive regional control is 97% and for N1-3 is 89%. Minor or moderate soft tissue ulceration was observed in 12 patients, including 3 cases that progressed to osteonecrosis. None required surgical intervention. No correlation exists between necrosis and tumor size or total dose.