Between October 1985 and October 1989, 75 previously untreated patients with stage III and IV non Hodgkin's lymphoma, large cell type, were treated with an alternating weekly chemotherapy regimen including the following drugs: week 1: Doxorubicin, vincristine, cyclophosphamide, bleomycin, and intrathecal (i.th.) methotrexate and cytarabine; week 2: Methotrexate with leucovorin rescue; week 3: Doxorubicin, ifosfamide with mesna, etoposide, and i.th. methotrexate and cytarabine; week 4: Methotrexate with leucovorin rescue. Complete responders after three cycles according to this schedule (12 weeks) were given 18 gys cranial irradiation and randomized between one additional cycle or three monthly CHOP (consolidation treatment). Among 66 evaluable patients, 53 achieved a complete remission (CR 80 per cent) and seven a partial remission (11 per cent). There were six failures, and nine early deaths during the initial phase, mostly due to septic problems. Forty-one of the 53 CR patients (77.3 per cent) have remained free of disease with a median follow-up of 15 months (1-49). Eight of the 12 relapses occurred during the first year, the four others at 13, 14, 16 and 38 months respectively. The 2-year survival was 63 per cent for the whole group, and 77 per cent for the CR group. No difference has been observed up until now between the two groups with different consolidation treatment. Therefore, this protocol seems to be able to produce a high rate of complete and durable remission. The analysis of prognostic factors suggests that some high-risk patients should be considered for intensification therapy with the support of autologous bone marrow transplantation.