Twelve patients with non-Hodgkin malignant lymphoma of poor prognosis were treated with heavy chemotherapy of the TACC type (cyclophosphamide 45 mg/kg/day i.v. X 4; cytosine arabinoside 200 mg/m2/12 hours i.v. X 7; 6-thioguanidine 100 mg/m2/12-hourly p.o X 7 and CCNU 200 or 250 mg/m2 p.o. single dose) followed by autologus bone marrow transplantation (853 to 20.000 CFUc/kg). The patients were divided into 2 groups depending on whether they received an induction treatment for large visible tumoral mass (group I: 3 initial presentations, 3 relapses) or a consolidation treatment for small residual tumour (group II: 6 complete and 1 partial remissions). The results show that autologous bone marrow transplantation shortens the duration of the therapeutic aplasia. White cell (greater than 10(9)/l) and platelet (greater than 50.10(9)/l) recovery was observed on days 12 (range 9-19) and 14 (range 8-27) respectively. In group I, 1 patient died of myocardial TACC toxity and acute renal failure on tumoral kidney; there were 2 failures and 3 complete remissions (8, 21, 45 + months). Remissions occurred in patients treated initially; the overall survival since diagnosis was 48+, 48+ and 60+ months. In group II patients there were 1 failure and 5 complete remissions persisting after a 2+ months to 30+ months follow-up; the overall survival was 23+, 24+, 27+, 42+ and 70+ months. The 3 failures in the series occurred in circumstances suggesting contamination of the cryopreserved bone marrow by tumoral cells. The toxicity, largely due to infection, of the TACC-bone marrow transplantation combination was tolerable. It was clearly lower in group II (6 patients, no septicaemia) than in group I (5/6 patients with septicaemia). These preliminary results confirm that there is room for autologous bone marrow transplantation in highly malignant non-Hodgkin lymphomas, particularly during complete remissions to facilitate the use of an aggressive consolidation chemotherapy.