There has been significant progress in the development of ex vivo machine perfusion for the nonischemic preservation of donor organs. However, several complications remain, including the logistics of using human blood for graft oxygenation and hemolysis occurring as a result of mechanical technology. Recently, hemoglobin-based oxygen carriers, originally developed for use as blood substitutes, have been studied as an alternative to red blood cell–based perfusates. Although research in this field is somewhat limited, the findings are promising. We offer a brief review of the use of hemoglobin-based oxygen carriers in ex vivo machine perfusion and discuss future directions that will likely have a major impact in progressing oxygen carrier use in clinical practice.