We achieved success in ABO-incompatible renal allografting after removing anti-A and/or anti-B antibodies from the recipient's plasma using double filtration plasmapheresis (DFPP). We report here the results of our initial 2 cases. Case 1 was a 40-yr-old female whose blood group was A+. The donor was her younger brother, a 37-yr-old male, whose blood group was B+. The human lymphocyte antigens (HLAs) were one haplotype identical, and the stimulation index of the mixed lymphocyte culture (MLC-SI) was 34. Case 2 was a 28-yr-old male whose blood group was B+. The donor was his father, a 58-yr-old male, whose blood group was AB+. The HLAs were one-haplotype identical as well, and the MLC-SI was 71. We carried out 4 sessions of DFPP pre-operatively; i.e. on days -6, -4, -2 and -1. 2.5 1 of plasma were treated with 500 ml of 4.4% plasma protein fraction in each procedure. The pre-operative target titer of anti-A/B antibody, measured by the saline tube test, was set at less than × 8. We also used 5 kinds of immunosuppressants. Cyclosporine was administered on day -2 beginning with 8 mg/kg/d, and its dose was modified according to the trough level. 500 mg of methylprednisolone were administered intravenously during the operation, and prednisolone was started on day 1 with 60 mg/d and tapered. Azathioprine was started on day -2 with 2 mg/kg/d for 7 d and 1 mg/kg/d thereafter. 5 mg/kg/d of gusperimus was given intravenously from day 0 for 5 d. 30 mg/kg/d of ALG was given intravenously from day 0 for 14 d. Along with these immunosuppressants, 0.1 mg/kg/h of nafamostat mesilate was administered intravenously from day 0 for 3 d, and 4 mg/kg/d of ticlopidine was given orally from day 3. X-Ray irradiation to the renal graft was not done. Following splenectomy standard renal allografting was performed. In Case 1, the titer of anti-B antibody was reduced from × 16 to × 4. In Case 2, the titer of anti-A antibody was reduced from × 32 to ×4. The post-operative courses of these 2 cases were satisfactory. Although our experience is limited, ABO incompatible kidney transplantation can safely be performed using DFPP.