Total body irradiation (TBI) was used as primary therapy for 58 previously untreated patients with Stage III or IV non-Hodgkin's lymphoma (NHL). 150 rad was administered, with 15 rad fractions twice a week, with careful monitoring of hematologic status. Thrombocytopenia was the most frequent complication, which resolved in all except 4 patients. Survival at 8 years was 52%, with 14% relapse-free survival. Patients with nodular histology had a more favorable prognosis than those with diffuse histology (median relapse-free survival of 24 vs. 12 months). There were 2 cases of erythroleukemia, which occurred after combination chemotherapy was given for relapse. Though TBI can offer complete remission and extended survival in advanced NHL, most patients eventually relapse and it should not be considered as a curative mode of therapy.