During the period 1966-1985, 66 patients were submitted for curative treatment of a carcinoma of the base of the tongue in the Netherlands Cancer Institute. Treatment consisted of radiotherapy (59 patients), surgery and post-operative radiotherapy (4 patients) and surgery alone (3 patients). Patients were staged according to the UICC (1982) and UICC (1987)/AJCC (1988) criteria. Regrouping by the latter system caused enlargement of the N2-group and of stage IV. The crude 5-year survival was 22%, the 5-year tumour control was 36% and the locoregional control was 47%. The most important prognostic factors for the tumour-free interval are the T-category (P = 0.01) and stage grouping (UICC 1982) (P = 0.022). The same factors predict the locoregional control (P = 0.005 and 0.02 respectively). Crude survival is lower in smokers, and in patients in poor general condition (P = 0.04 and 0.007 respectively).