Transfusions are withheld, whenever possible, from patients with aplastic anaemia who are potential bone marrow transplant recipients because of the increased risk of graft failure associated with transfusions prior to transplantation. Family members are specifically excluded as blood product donors to reduce the likelihood of sensitizing the recipient to antigens shared by the blood and bone marrow donor. This policy of not using family members, particularly the HLA-matched bone marrow donor, to provide blood products prior to transplantation has been extended to leukaemia as well. To evaluate this policy we reviewed the outcome of bone marrow transplantation in 18 patients with leukaemia transfused prior to transplantation with platelets and/or leucocytes from related family members. In 15 cases in which the outcome could be evaluated, engraftment was rapid and graft failure did not occur. Transfusion of blood products from related family members to patients with leukaemia prior to transplantation does not appear, therefore, to increase the risk of graft rejection.