The ability to deliver high-dose chemotherapy with or without radiotherapy followed by marrow rescue has made marrow transplantation the treatment of choice for children with AML in first remission, juvenile CML, and adult-type CML in chronic phase. For patients with ALL or NHL who relapse, transplantation in second remission represents a reasonable therapeutic option. The role of marrow transplantation for patients in the advanced stages of their disease will continue to be explored to develop promising new therapies, which may improve results of transplantation earlier in the disease course. Development of transplant preparative regimens that have the same or improved therapeutic efficacy with less late effects is especially important for growing and developing children. In the meantime, all children who have received a marrow transplant must be followed for development of delayed effects, which may not appear until years after the transplant procedure. Children who are cured of their leukemia continue to occasionally visit the pediatric hematologist/oncologist, but they do so less often with increasing time after curative therapy. Thus, it is necessary for the primary care pediatrician to be familiar with the details regarding the child's previous therapy in order to anticipate and to be prepared to treat the delayed effects. Attention to school performance is of particular importance for early identification of those children who may need special educational attention. Advances in the treatment of children with leukemia continue to be made both with chemotherapy and with marrow transplantation that should result in greater numbers of children being cured.(ABSTRACT TRUNCATED AT 250 WORDS)