Twelve patients with non-Hodgkin's lymphomas of poor prognosis were treated by TCC high-dose chemotherapy (cyclophosphamide 45 mg/kg/day × 4, cytosine arabinoside 200 mg/m 2 i.v. q 12 hr × 7,6-thioguanin 100 mg/m 2 p.o. × 7 and CCNU 200 or 250 mg/m 2 p.o., single dose) followed by autologous bone marrow transplantation (ABMI) (infused dose: 853–20000 CFU-c/kg ). Patients were divided into 2 groups: those in primary therapy with high tumor load (group 1; 3 initial diagnoses, 3 relapses) and those in consolidation therapy for a low tumor load (group 2; 5 complete and 1 partial remissions). Results show that: (1) the aplasia following autologous bone marrow transplantation was short. Leukocyte (>10 9 / l ) and platelet (>50 × 10 9 / l ) recoveries were observed on day 12 (range, 9–19) and day 14 (range, 8–27). (2) In group 1 there were 3 complete remissions (8, 21, 45+ months and 3 failures, including 1 death to toxicity of TACC. The 3 remissions occurred in patients in primary therapy and overall survival of these patients from the time of initial diagnosis was 48+, 48+ and 60+ months . In group 2 there were 5 persisting complete remissions (12+ to 40+ months ) and 1 failure. Overall survival of these patients was 23+, 24+, 27+, 42+ and 70+ months . In both groups failures were associated with contamination of the frozen marrow by tumor. The toxicity of the association TACC + ABMT was acceptable and dominated by the risk of pericardial effusion and infection. The latter was absent in group 2 and occurred in 56 cases in group 1. These preliminary results indicate that autologous bone marrow transplantation has a possible role in the aggressive treatment of non-Hodgkin's lymphomas of high-grade malignancy and that its use should preferentially be in the consolidation mode.