Use of leucocyte-depleted blood components reduces refractoriness to platelet transfusions, but the cost-effectiveness of this policy has been in doubt. We retrospectively analysed data of 115 patients with acute myeloid leukaemia (AML), treated according to a standardized cytostatic protocol. Fifty patients had received standard (STD) platelet concentrates (PCs) and red blood cell concentrates (RBCs). Sixty-five patients had received leucocyte-depleted (L-D) components, with fewer than one million leucocytes per unit. Refractory patients (22% of the STD group and 3% of the L-D group) were excluded from further observations. There were no differences between the groups during the first cytostatic treatment period. Thereafter, significantly fewer PCs and RBCs were transfused to the L-D group. In the L-D group, granulocytopenia (< 0.5 x 10(9)/l) and thrombocytopenia (< 50 x 10(9)/l) were shorter, the lowest leucocyte counts were higher, serious infections were less common (44% v 59%), and the patients spent fewer days in hospital. The median relapse-free survival (RFS) was longer in the L-D group than in the STD group. We conclude that leucocyte depletion of blood components has favourable effects on the recovery of haematopoiesis, consumption of blood components, occurrence of serious infections, and relapse-free survival in AML.