A retrospective study of 65 patients with Hodgkin's disease (clinical stage I: 11 cases; stage II: 54 cases) included an analysis of the causes of therapy failure. Twenty-five of the 65 patients had been treated by regional irradiation (thoracic mantle or inverted Y field) restricted to only one side of the diaphragm; 27 patients had received the same irradiation followed by chemotherapy (MOPP). The subjects were irradiated on both sides of the diaphragm; 3 of these had received the same radiotherapy followed by chemotherapy (MOPP). Relapses in the irradiated fields were rare. Relapses in the areas bordering the irradiated fields were definitely the result of faulty delivery. Better evaluation of the precise extent of the disease, particularly by laparotomy, would lead to improved initial treatment (radio- or chemotherapy). The availability of improved irradiation techniques and a better choice of indications, particularly concerning the timing for chemotherapy, should result in maximal reduction of therapeutic failures in the early stages of Hodgkin's disease.