A group of 12 children and 5 adults, all with diffuse non-Hodgkin's malignant lymphoma (NHML), received massive chemotherapy regimens. The stages of the disease were as follows: 7 patients were in second complete remission; 6 in a progressive phase of the disease; and 4 in first complete remission which occurred late in the course of the disease. All patients received BACT (BCNU+aracytine+cyclophosphamide+thioguanine) or TACC (idem with CCNU) at different dose levels: 6/17 received 10 Gy total-body irradiation (TBI) after BACT treatment; 16/17 received autologous bone marrow transplantation (ABMT) previously stored in liquid nitrogen to combat the medullary effects of chemotherapy. Direct therapy-related deaths occurred in 4/17 patients (1 Aspergillus endocarditis; 1 Moskowitz syndrome; 1 veno-occlusive disease of the liver; and 1 Escherichia coli pneumopathy) and 6/17 patients relapsed between days 25 and 70 of treatment. Seven out of these 17 patients are still alive NED 102-900 days (mean, 475 days) after the beginning of therapy without receiving maintenance treatment. Massive chemotherapy could thus be the best treatment for NHML in relapse, but the high percentage of early therapy-related deaths is a strong limiting factor for patients before relapse.