During the past decade, the results of BMT have dramatically improved with an increasing number of long-term survivors in diseases that were previously fatal. These results are gratifying and probably indicate an increased cure rate through the use of marrow transplantation. However, the recent advances have occurred partially due to better patient selection for transplantation as in the untransfused aplastic patient or the leukemic patient in early remission. Problems remain which still limit both the success and applicability of marrow transplantation. These are the challenges of the 1980s which, if overcome, will lead to the extension of BMT to other blood and genetic diseases.