Disclosed herein are solutions for use with machine perfusion of one or more organs. In some embodiments, the solutions comprise acellular cross-linked hemoglobin in a physiologically acceptable medium. Also disclosed herein are methods for machine perfusion of one or more organs, for example utilizing the disclosed perfusion solutions. In some embodiments, the methods include perfusing an organ with an oxygenated solution (such as the disclosed solutions) which is at a temperature between about 12-37° C., for example at a temperature of about 21° C.