For physiologic as well as oncologic reasons, there has been an increasing interest in radiation therapy as the primary treatment of base of tongue carcinoma. At Memorial Sloan-Kettering Cancer Center, we have used such a plan, using external beam conventional therapy in combination with an interstitial boost of iridium 192 to the primary site, plus planned neck dissections in selected patients. Between 1981 and 1986, 17 patients with untreated base of tongue squamous cell carcinoma were treated in this manner. Thirteen of the 17 are disease-free as a result of this therapy. Two patients have failed locally, yielding an actuarial local control of 87% at a median followup of 2 years. These data would suggest that primary radiation that includes interstitial therapy as part of the plan, along with neck dissection in certain situations, is a worthwhile method management of base of tongue carcinoma.