The role of high dose chemo-radiotherapy with autologous bone marrow transplantation in the treatment of neoplasia remains to be clearly defined. Because of the iatrogenic morbidity, mortality and high cost of the supportive care required during the post-transplantation period of prolonged marrow aplasia, intensive therapy remains a sophisticated procedure lacking proper evaluation in clinical trials. We report here that when autologous bone marrow cells are supplemented with a small number of peripheral blood nucleated cells collected after prior myelosuppressive chemotherapy, complete hematological recovery is so prompt that myeloid toxicity appears no longer the major limiting factor of high-dose chemo-radiotherapy. The increased therapeutic index made possible by the procedure will allow us to address the issue of whether intensive cytoreductive therapy can be useful as initial treatment of selected tumors with curative intent.