Introduction. Bone marrow (BM) has been utilized as a source of stem cells for transplantation for many years. Although the use of BM has decreased with the advent of mobilized stem cells, utilization is increasing once again due to the lower rate of chronic GVHD associated with BM as a stem cell source. There is no generally accepted technique for harvesting BM. Protocols vary both in relation to the volume of each aspirate and the number of aspirates performed at each puncture site. .