In the rat model of heterotopic auxiliary liver transplantation, graft re-arterialization may influence the outcome of inter-liver competition. This was investigated in the current study using two transplanted groups with or without graft re-arterialization. Immediately after reperfusion, the re-arterialized grafts showed significantly higher bile flow rate and bilirubin excretion than the grafts without re-arterialization. DNA synthesis rate was also increased more drastically in the re-arterialized group following the transplantation. Without re-arterialization, the rats developed more pronounced cytolysis and cholestasis. Among the long-term survivors, all healthy re-arterialized grafts regenerated, whereas 5/6 non-re-arterialized grafts atrophied. These data demonstrate that the re-arterialization increases graft survival by improving early hepatic function, enhancing regenerative response and preventing post-transplant biliary complications in this rat model.