Between July 1983 and May 1987 143 untreated patients with Hodgkin's lymphoma in stages I-IIIA with risk factors qualified for the HD1 protocol, and 230 patients in stages IIIB/IV qualified for HD3. Patients in HD1 received a combined chemo-radiotherapy (2 x COPP + ABVD + 20 Gy EF vs. 40 Gy EF). 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, 73 of 89 evaluable patients (82%) achieved a complete remission. The survival of patients in stages I-IIIA with risk factors treated according to HD1 is as good as the survival of patients in stages I and II without risk factors. In HD3, 86 of 137 patients (63%) achieved complete remission after induction chemotherapy with 3 x 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 76% complete remissions in stages IIIB/IVAB were achieved. An ESR greater than 80 mm/h was the most significant single risk factor in stages IIIB/IV for induction of CR and freedom from progression.