Seventy-eight previously untreated patients with clinical stage (CS) I and II (42 patients) and CS III and IV (36 patients) and non-Hodgkin's lymphoma (NHL) were treated with systemic chemotherapy only. All patients had intermediate or high grade lymphoma. Two different regimens were used: bleomycin, adriamycin, cyclophosphamide, vincristine and prednisone (BACOP); and a combination of methotrexate with folinic acid rescue, epirubicin, cyclophosphamide, vincristine, prednisone and bleomycin (MECOP-B), for 57 and 21 patients respectively. Objective clinical remission was achieved in 90% of the cases, of which 73% were complete. Complete remission (CR) was demonstrated in 90% and 53% of patients with CS I + II and III + IV respectively (P = 0.0008). Two variables, bone marrow and liver involvement, were negatively associated with CR rate in a multivariate analysis. The actuarial overall survival for the entire group was 65%. The median survival for complete responders has not been reached, but a projected 80% relapse-free survival at 3 years is estimated. The Cox proportional hazards model predicted that advanced stage (CS III and IV) and pretreatment lactic dehydrogenase serum level above 400 iu/l (N less than 200 iu/l) independently influenced survival adversely. The latter prognostic variables were used to identify several groups with different risk probabilities. Despite an apparent comparability between patients receiving the two regimens, no significant difference in response or survival rates was noted between the two protocols. We conclude that the results of systemic chemotherapy compared favorably with radiation therapy for early stage disease and is an acceptable strategy for developing countries with limited availability of radiotherapy facilities. Based on certain risk factors, therapy should be individualized so that more intense regimens, with or without radiation, should be offered only to those patients in the high risk group at highly specialized centers.