Within the supraglottic larynx, two subregions can be distinguished: the epilarynx and the lower supraglottis. Tumours arising in these structures have very different clinical presentations and prognosis. Management should be adjusted accordingly. Between 1962 and 1977, 325 patients with supraglottic cancer were seen, of whom 317 presented as untreated cases. In 171 patients (54%) the tumour originated in the lower part of the supraglottis. In this group 61% had T1 or T2 lesions, 23% had palpable neck nodes. In 130 of these patients, the initial treatment was irradiation. At 5 years, actuarial survival was 55% (uncorrected) and local control was 77%. The larynx was preserved in 61% of patients. Tumour stage had only limited influence on treatment results, but the presence of neck nodes was very important for prognosis. The best survival rate was observed in patients with T1 or T2, N0 lesions. Epilaryngeal tumours were seen in 146 patients (46% of all supraglottic tumours). In this group, only 40% had T1 or T2 lesions and 47% had palpable nodes. In the 110 patients primarily treated with radiotherapy, uncorrected actuarial survival was 36%, local control was 56% at 5 years. The voice was preserved in 45% of patients. Tumour stage had no influence on prognosis, but the presence of lymph nodes was a very important prognostic discriminant. A dose-response relation was observed in the range between 40 Gy in 4 weeks and 65 Gy in 6.5 weeks, above this dose level no further improvement was observed. It is remarkable that, although the presence of palpable neck nodes at diagnosis is the most important factor determining local control and survival, only in 23 out of 104 local or regional recurrences was the relapse found in the neck nodes. In 75 patients, the primary treatment was a combination of radiotherapy and surgery (40 lower supraglottic and 35 epilaryngeal tumours). Survival at 5 years was 62%, local control 77%. While these results were about equal in both subsites, both survival and local control were higher than in patients treated with radiotherapy alone. In our institute, the complication rate of surgery after preoperative irradiation was low. From our data, it appears that a laryngectomy is to be preferred for all patients with palpable neck nodes and also for all T3 and T4 lesions of the lower supraglottis. Radiotherapy should probably be reserved for small (T1 and T2) tumours of the lower supraglottis and for epilaryngeal cancer without neck nodes.(ABSTRACT TRUNCATED AT 400 WORDS)