From November 3, 1975, to May 31, 1989, 711 (548 living-related and 163 cadavers) kidney transplantations were performed in our centers. In the final 2 years, 15 ABO-incompatible living related kidney transplantations were performed. In 4 cases, the recipient's blood groups was O and the donor's A1. In 3 cases the blood group of the recipient was A1and the donor's AB, two patients were B with the donors A1and the other 2 were O with donors B. The other 3 recipients group was B and the donors' were AB. The donors' and recipients' HLA-AB typing showed one haplotype matching in 12 and two haplotypes matching in 3 patients. The donors were mothers in 7 cases, sibling in 5, and father in 3 cases. At least 3 weeks before the renal transplantation, donor-specific skin grafts and subsequently splenectomy were performed on 9 recipients, but on 6 recipients without splenectomy. Following the skin graft, cross-match was done starting from the 15th day and then continued every week. The immunosuppression, which consisted of triple drugs (0.5 mg/kg prednisolone, 2 mg/kg cyclosporin-A and 2 mg/kg azathioprine) was followed by skin graft. Renal transplantation was performed according to cross-match and skin graft results, and all recipients prior to surgery received at least two sessions of plasmapheresis. Regular dose of immunosuppression that included triple drugs were used after the kidney transplantation and then Orthoclone OKT-3 and plasmapheresis were applied during the rejection episodes without bolus therapy. All patients were followed for 5 to 24 months (ave. 14,13 months). All grafts except one showed immediate function; one hyperacute rejection was encountered and the grafts were lost. Four patients displayed acute rejection on the 3rd to 7th days of the posttransplantation period. The conclusions were: (a) Effective and special immunosuppressive methods are necessary for renal transplantation in ABO-incompatible patients. (b) Donor specific skin grafts can be used as a simple guide factor in ABO-incompatible kidney transplantation.