Autologous blood stem cell transplantation (auto-PBSCT) has increasingly been incorporated into the treatment of various malignancies. Auto- PBSCT provides several advantages over auto-BMT, but sometimes requires several collections of PBSC. We have retrospectively analyzed the time requirements and cost effectiveness of PBSC collection in Okayama University Hospital between 1994 and 1997, in which PBSCs were mobilized by chemotherapy and granulocyte colony-stimulating factor in 85 patients. During the 1994-1995 period, PBSCs were collected by apheresis, which was timed by leukocyte count and carried out by attending physicians, and cryopreserved at<5×10⁷cells/ml concentrations. During 1996-1997, PBSC harvests, in which the number of apheresis was adjusted by the number of CD34⁺ cells collected at each harvest, were predicted by circulating immature myeloid cell count, and carried out by personnel of the Division of Blood Transfusion. Collected cells were cryopreserved at<1×10⁸cells/ml. From the 1994-1995 to 1996-1997 periods, the average number of apheresis, the number of cryopreserved bags, and the time and cost required for aphereses and cryopreservation decreased from 3.5 to 1.4 aphereses, from 12.1 to 4.5 bags, from 13.6 to 7.1 hours and from 317 to 113 thousand yen per patient, respectively. Our experience suggests that the time requirements and cost effectiveness of PBSC harvest may be improved with precisely timed apheresis by skilled personnel and with appropriately defined cryopreservation.