The primary objective of organ preservation is to deliver a viable graft with minimal risk of impaired postoperative graft function. In current clinical practice, preservation of transplanted organs is based on hypothermia. Organs are flushed and stored using specific preservation solutions to reduce cellular metabolism and prevent cell swelling. However, the ongoing organ donor shortage and consequent expansion of donor criteria to include the use of grafts that would once have been discarded as unsuitable have underlined the need for a technique that prevents any further damage during the preservation period. The principle of normothermic machine perfusion preservation is the maintenance of cellular metabolism in a physiological environment throughout the preservation period. Normothermic preservation, at least in theory, thereby overcomes the 3 major weaknesses inherent in traditional static cold storage by (1) avoiding ischemia/reperfusion injury, (2) avoiding cold injury, and (3) allowing viability assessment. Furthermore, normothermic machine perfusion might transpire to be the ideal vehicle to deliver other therapeutic interventions during preservation to modulate and optimize the graft before transplantation. By restoring function in marginal donor organs and enabling the clinician to appraise its viability, the donor pool might be greatly expanded.