Donor apheresis has played an important role in the Japanese blood program. Donor plasmapheresis was introduced to increase source plasma in 1986 and accounted for 20.8% of all donations in 1995. The total volume of source plasma increased from 104 x 10(3) L in 1989 to 636 x 10(3) L in 1994, and the rate of self-sufficience of factor VIII reached 100% in 1994 (excluding recombinant products). This rate had been below 10% in 1991. The supply of platelet products has increased rapidly in Japan and reached 7.19 million units in 1995. The number of platelet products obtained with the apheresis procedure accounted for 99.99% in all supplied products in the Hokkaido Red Cross Blood Center. Thus, it can be seen that platelet apheresis has played an important role in securing a sufficiency of the products. Another advantage of platelet apheresis is the reduction of residual leukocytes in the products, which helps to avoid donor antigen exposure and prevent febrile nonhemolytic reaction. The technique of apheresis has been applied in cancer therapy. Peripheral blood stem cell (PBSC) transplantation has been performed not only in autologous but also allogeneic settings instead of bone marrow transplantation. In the authors' experience, sufficient numbers of progenitor cells could be collected in 85.7% of patients within 2 leukaphereses; thus, apheresis will become more important in this field.