Two children with Ki-1 antigen-positive, non-Hodgkin's lymphoma received high-dose chemotherapy, fractionated total body irradiation (TBI), and allogeneic bone marrow transplantation. Both patients had relapsed multiple times on conventional chemotherapy and radiation therapy. Following transplantation, there was successful engraftment with disappearance of clinical signs and symptoms of their disease. As of June 1, 1989 they are in continuous unmaintained complete remission, 56 and 40 months, respectively, after bone marrow transplantation.