We have categorized reperfusion injury into (1) warm ischemia/reperfusion injury and (2) cold storage/reperfusion injury. Warm ischemia/reperfusion injury is relevant to shock and hepatic surgery, whereas cold storage/reperfusion injury occurs when the liver is procured and transported for transplantation. Different stages of reperfusion injury; cells that mediate each stage; and cytokines involved are described. Understanding the specific cells and cytokines involved in causing reperfusion injury and their timing will encourage the development of therapeutic strategies aimed at preventing and diminishing the consequences of reperfusion injury.