Fourteen patients with non-Hodgkin's lymphoma (NHL) of high-grade malignancy were treated with cyclophosphamide and total body irradiation followed by autologous bone marrow transplantation (ABMT). All patients were pretreated with conventional chemotherapy. Three of four patients with drug-resistant disease achieved complete remission (CR), but relapse occurred within six months. Four patients in partial remission (PR) achieved CR; one died because of sepsis, two relapsed within six months, and one is still in CR 28+ months later. Six were treated in CR, five in first CR, and one in second CR. From these six patients (who received this treatment as consolidation therapy), five are in unmaintained CR seven to 31+ months after ABMT (one patient died of a secondary illness). There were two therapy-related deaths, both in patients with a poor clinical condition. Toxicity of this treatment was mild for those receiving transplants who were in better condition. These preliminary results suggest that intensive cytoreductive therapy followed by ABMT may improve disease-free survival in patients in NHL of high-grade malignancy in CR.