We report the case of an ABO-incompatible kidney transplant recipient who died suddenly following a good transplant course of 12 years. For 10 years after transplantation, the graft function had been stable (s-Cr: 1.0-1.5 mg/dL), although chronic hepatitis C had developed, with elevation of transaminase. In the 11th year, he was admitted into the hospital with low-grade fever and general fatigue. Jaundice and anaemia progressed, and he died 2 months after admission. The autopsy diagnosis was: (1) post-renal transplantation state, (2) phlegmonous enterocolitis with septic infarction, (3) cellulitis and necrotic myositis, and (4) sepsis. The transplanted kidney graft showed well-preserved glomeruli and tubules, corresponding to chronic allograft nephropathy (CAN) grade Iota (ci1, ct1, cv1), according to the Banff classification. The pathological changes observed in this long-surviving ABO-incompatible kidney graft were similar to those of an ABO-compatible graft, although its degree was milder.