In the period 1963-1991, a total of 277 consecutive patients with malignant tumours of the nasal cavity and paranasal sinuses were treated at Aarhus University Hospital. The major histological types included squamous cell carcinoma (46%), lymphoma (14%), adenocarcinoma (13%), and malignant melanoma (9%). Kaplan-Meier estimates of 5-year corrected survival (death from cancer) showed the best prognosis for adenoid cystic carcinoma (87%), adenocarcinoma (65%) and lymphoma (56%), and the poorest prognosis for undifferentiated carcinoma (17%) and malignant melanoma (24%). The 5-year corrected survival for squamous cell carcinoma was 35%. Of the 180 patients with treatment failure, the vast majority occurred locally (n = 166); a minor proportion was regional (n = 23) or distant (n = 30). For the 195 patients with carcinoma, the following parameters were of statistical prognostic significance (5-year corrected survival): histological differentiation (moderate-well 65% vs. poor 22%), primary T-site (nasal cavity 56% vs. maxillary antrum 39% vs. other sinuses 24%), tumour stage (T2 68% vs. T3 37% vs. T4 29%), nodal stage (N0 48% vs. N1-3 21%), treatment (radiotherapy + surgery 56% vs. radiation alone 35%).