For patients receiving autologous bone marrow transplantation for lymphoma striking decreases in length of stay and almost every charge category occurred, including platelet transfusions,when ABO-identical platelets/filters were used. The ABO-identical-filtered leukodepleted recipient group had significantly reduced mean total hospital charges ($67,045 vs. $113,454, p=0.0003), total ancillary service charges ($30,165 vs. $56,051, p=0.0004) and pharmacy charges ($10,027 vs. $17,671, p=0.0008) compared with the recipients of ABO-unmatched-unfiltered transfusions. The mean savings in blood component purchase were $4,127, which exceeded the mean costs of purchasing red cell and platelet filters ($643). For patients undergoing remission therapy for acute leukaemia, the need for most support services also decreased significantly in the ABO-identical-filtered group. Moreover the filter cost per patient was less than the mean platelets transfused costs ($875 vs $3283).