Review of prognostic factors at Memorial Hospital in New York City has shown that adult patients with large-cell lymphoma (diffuse histiocytic lymphoma by Rappaport classification) who have high lactic dehydrogenase (LDH) and/or bulky mediastinal or abdominal disease are destined to do poorly with conventional combination chemotherapy, with a 2-year disease-free survival of about 20%. Patients who relapse after conventional combination chemotherapy have a similar poor prognosis. Thirty-one such patients with lymphoma were studied to evaluate the efficacy of intensive radiotherapy (hyperfractionated total body irradiation [TBI] [1,320 rad]), and cyclophosphamide (60 mg/kg/d for two days) followed by autologous bone marrow transplantation (ABMT). Our results show a disease-free survival advantage (P = .002) for 14 patients who underwent ABMT immediately after induction of remission with 79% surviving at a median follow-up 49.2+ months, compared with a median survival of 5.2 months for 17 patients administered ABMT while in relapse and/or after failing conventional treatment. Our results support the use of aggressive therapy as early treatment for patients with poor prognostic features.