Between July 1983 and September 1986 358 untreated patients with Hodgkin's lymphoma qualified for the protocols HD1 (stages I to IIIA with risk factors), HD2 (stage IIIA), and HD3 (stages IIIB and IVAB). Patients in HD1 received a combined chemo-radiotherapy (2 X COPP/ABVD + 40 Gy EF vs. 2 X COPP/ABVD + 20 Gy EF). Patients in HD2 were randomized into radiotherapy (TNI 40 Gy) vs. combined chemo-radiotherapy (2 X COPP/ABVD + 20 Gy IF). Patients in HD3 received induction chemotherapy (3 X COPP/ABVD) and were randomized into consolidation by radiotherapy (20 Gy IF) vs. chemotherapy (1 X COPP/ABVD). In HD1, 51 out of 65 evaluable patients (78%) achieved a complete remission. The survival of HD1 patients is as good as the survival of patients in stages I and II without risk factors. In HD3, 58 out of 93 patients (62%) achieved complete remission after induction chemotherapy with COPP/ABVD. This is significantly better than the 31% complete remission rate observed in a pilot study with COPP alone (p less than 0.01). Including salvage therapy (radiotherapy in case of persisting nodal disease; chemotherapy with 4 X CEVD in case of persisting disseminated disease), a total of 71% complete remissions in stages IIIB/IVAB were achieved. The progression-free survival of HD3 patients who received consolidation therapy is significantly longer than of patients who refused consolidation therapy.