The University of Wisconsin solution discovered in 1987 by Belzer and associates, has dramatically changed the logistics associated with liver transplantation. The extension of hypothermic preservation time has mode at possible: a) to operate in a semi-elective situation, rather than urgent; b) to improve patient selection and to be able to admit them from distant locations, and c) to reduce postoperative complications with a better quality of organ preservation. In the present work we illustrate the pathophysiological background and the rationale behind the various chemical constituents included in the new solution, emphasizing the antiedemogenic effect. Furthermore we report some experimental data on the role of energy level (ATP) and intracellular pH in the monitoring of liver preservation. Together with the improvements of surgical technique and immunosuppression, the new solution of the University of Wisconsin represents a fundamental step in the development of organ transplantation.