About 80% of carcinomatous lesions of the lip are smaller than 2 cm in diameter, have little tendency to infiltrate, grow in the lower lip, are histologically well differentiated and do not have, or develop later, regional metastases. Of these carcinomas 95% are cured by the various methods of radiotherapy. The criteria for a more serious prognosis, such as expansive growth, deeper infiltration, location on the upper lip and/or the commissures, undifferentiated grading and regional lymphatic metastases, are found only in a minority of patients with carcinoma of the lip. However, even for tumors of the T3 category rates of cure of over 90% are reported, as confirmed by our own results with supervoltage irradiation with fast electrons of the betatron during the years 1961-1970. The techniques and indications of interstitial Curietherapy with iridium-192 wires are described. The treatment of primary lymphnode metastases, which should be confirmed histologically or cytologically before therapy, is described in detail. Neck dissection is superior to irradiation therapy. General elective neck dissection, as normally performed for carcinoma of the oral cavity, is not justified because of the low rate of metastases and the results of elective therapy. A case report demonstrates the poor prognosis in patients with regional fixed metastases.