Sixty-five patients with invasive squamous cell carcinoma of the supraglottic larynx received irradiation with curative intent between 1975 and 1984, with a 5-year actuarial survival of 48% and a local control rate of 70%. Five-year survivals for clinical Stages I, II, and III + IV were 60, 53, and 52%, respectively; local control rates were 88, 76, and 63%, respectively. These patients included one treated with preoperative irradiation, 35 treated with surgery followed by postoperative irradiation, and 29 treated with radiation therapy alone. In the surgery plus irradiation group, 5-year local control was 93% for clinical Stages I + II (14 patients), and 61% for clinical Stages III + IV (21 patients). Three patients had pathologic Stage II disease, with the remainder demonstrating a higher pathologic than clinical stage. Multiple positive nodes predisposed to local/regional recurrence, while no relationship could be established between recurrence and extracapsular nodal spread, positive margins, emergency tracheostomy, total versus less-than-total laryngectomy, radiation field size, radiation dose, or delay until radiation therapy, probably because of patient numbers. Six patients, five with positive nodes, developed distant metastases, and three developed second primary tumors outside the head and neck region. In the radiation therapy alone group, 5-year local control rates were 86, 59, and 53% for clinical Stages I (7 patients), II (11 patients), and III + IV (11 patients), respectively. However, three of four Stage II local/regional failures were surgically salvaged for periods greater than 30 months, for an ultimate Stage II local control of 89%. No relationship could be established between local control and radiation dose or field size, again probably because of small patient numbers. Three patients developed distant metastases, and eight developed second malignancies, one within the irradiated volume. Fifteen patients developed acute toxicity during irradiation, and there were eight chronic complications, five requiring surgery; toxicity was more common in the group treated with radiation alone. Radiation therapy alone with surgical salvage is an effective, function-preserving treatment for clinical Stages I and II carcinoma of the supraglottic larynx, and appears to yield local control and survival comparable with that of combined irradiation and surgery in more advanced disease.