Twenty-eight patients with malignant lymphoma were treated with high dose chemo or chemoradiotherapy and allogeneic or autologous bone marrow transplantation. They can be divided in two groups: Group 1: (19 pts) consisted in patients in relapse or in n complete remission (n greater than 2) (high risk patients); Group 2 (9 pts) consisted in patients in first or second complete remission at time of bone marrow graft (standard risk patients). Complete remission was achieved in 11/17 patients evaluable for response (65%). Duration of response is very different for two groups: in group 1, all patients relapsed within a median of 2 months (range: 1-12) and died within a median of 7 months (range: 2.5-15). In group 2, 7/9 are alive and well in unmaintained CCR in a median of greater than 18 months (range: greater than 15- greater than 36) (P less than 0.01). This experience shows the feasibility of this approach, the obvious antitumoral activity of these conditioning regimens and invited us to use such therapy at an earlier stage of the disease.