Patients with malignant parotid tumors were treated at two different centres with slightly ionizing radiation (110 patients) and neutron therapy (15 patients). The treatment results are compared. The principles of comparison applied in this analysis are identical. The histologic classification was made according to the W.H.O. recommendation of 1972 and the staging according to Becske. Local tumor control is the criterion applied in the comparative assessment of both methods. The analysis has shown that there is no significant difference in the treatment results within the individual stages of tumor's advancement after application of an orthovolt therapy and a telecobalt therapy. Patients treated in early stages (stages I and III) had a substantially higher rate of local tumor control (72%) than patients in advanced stages (46%, stages III and IV). A more favorable treatment results was achieved by neutron therapy in all stages of tumor's advancement. In this case the rate of patients with local tumor control (87%) was significantly higher than after radiotherapy with slightly ionizing radiation (46%).