There have been few studies of the immune status of long-term follow-up patients after living-donor kidney transplantation. We investigated the immune status from the immunologic and pathologic standpoint of three long surviving recipients who had received renal grafts more than 30 years earlier. Anti-HLA antibodies that had not been present before transplantation were detected in one recipient with three HLA mismatches. One recipient with identical HLA showed positive for the crossmatch test, but not for the panel reactive antibody test (PRA), thus showing that this patient had HLA antibodies against HLA minor histocompatibility antigens, etc. Only one patient with established microchimerism was stable without any antibody production. Pathologically, chronic allograft nephropathy with C4d staining suggestive of antibody-mediated rejection was observed in both patients with HLA antibodies. Physicians should clinically manage patients by always bearing in mind the presence of anti-donor antibodies during long-term regular follow-up of transplanted kidneys.