The natural history of malignant lymphomas of the oropharynx and their response to treatment are described by evaluating the course of 41 patients, who after histological verification underwent radiotherapy in the Radiological Clinic of Kiel University between 1965 and 1979. The analysis of the malignant non-Hodgkin lymphomas according to the "Kiel classification" reveals a clear predominance of the germinal center tumors and the high grade malignancies. The long-term results of treatment show a good prognosis for clinical stages I-II1 (two adjacent lymph node or extranodal regions involved above the diaphragm, "Ann Arbor"-classification modified by Musshoff) with a 85% probability of both survival and freedom of disease. For clinical stages II2-IV long-term actuarial survival and disease free survival were lowered to 51% and 23%. Whereas in 93% a complete tumor regression could be achieved by the primary treatment, one third of these patients developed a recurrence of the disease, mainly caused by incomplete therapy, such as missing the "extended field" radiotherapy or a necessary chemotherapy because of old age, myelodepression or simply refusion of further treatment. According to the results of this study chemotherapy seems to be necessary from clinical stage II2 on (two distant lymph node or extranodal regions or three or more regions located anywhere involved above the diaphragm). Finally a refined locoregional irradiation technique for malignant lymphomas of the oropharynx is described: fast electrons and cobalt rays in daily alternation for the posterior cervical lymphnodes. Last not least we present the unusual treatment schemes of the "Kiel Lymphoma Study Group" for malignant non-Hodgkin-Lymphomas of different histologies and stages.