Within the past year substantial progress has been made in understanding the molecular changes underlying the development of acute leukemia. Development of molecular probes allowed substantial improvements in the detection of minimal residual disease. Pilot studies underlined the correlation between the expression of the multidrug resistance gene and the likelihood of response to chemotherapy. The expression of mdr-1 apparently correlates with the expression of certain surface antigens like CD34 and CD7, which by themselves are associated with the expression of bcl-2 and poor treatment response. The value of hematopoietic growth factors to overcome drug resistance has not yet been clearly demonstrated in clinical trials, but they seem to reduce early mortality in elderly patients with acute myeloid leukemia when given after chemotherapy. Substantial progress has been made in the understanding of molecular changes in acute promyelocytic leukemia. Combination of all-trans retinoic acid and chemotherapy is the treatment of choice in acute promyelocytic leukemia. Allogeneic bone marrow transplantation proved to be superior in certain high-risk groups of patients with acute leukemia, including those with acute lymphoblastic leukemia with the bcr-abl configuration. The value of allogeneic bone marrow transplantation from related and unrelated donors, as well as the value of autologous bone marrow transplantation, is increasingly defined in randomized trials.