Nine individuals between 15 and 43 years of age with non-Hodgkin's lymphoma underwent allogeneic marrow transplantation following busulfan 16 mg/kg and cyclophosphamide 120 mg/kg. These individuals were not considered optimal candidates for autologous transplantation chiefly because of marrow involvement or resistance to chemotherapy. All patients engrafted and eight achieved complete remission. Three patients relapsed; one patient died of transplant-related complications. Five individuals are disease-free survivors between 103 and 1169 days following transplantation. Of three individuals with relapsed Burkitt's lymphoma none experienced a sustained disease-free interval following transplantation. Three of four individuals with large cell or lymphoblastic lymphoma are surviving 585 to 1169 days following transplantation. Allogeneic marrow transplantation following busulfan and cyclophosphamide appears reasonably safe and is effective in selected patients with non-Hodgkin's lymphoma who are not good candidates for autologous marrow transplantation.