Liver transplantation (LT) has been established as the most effective therapy for acute and chronic liver diseases over the last few decades due to its excellent long-term results. At the beginning of the LT era, donor organs were allocated based on waiting time. However, as the number of LT candidates consistently increased, a specific allocation system became necessary to prioritize the large number of patients waiting for a limited pool of organs. The LT candidates were categorized into different urgency levels based on their hospital status, degree of liver disease as measured by the Child-Turcotte-Pugh score, and accompanying complications of liver disease, such as ascites, variceal bleeding or hepatocellular carcinoma. The majority of European countries, including Austria, still rely on this organ allocation system. In the United States, however, a new allocation system based on the risk of death without transplantation, assessed by the Model for End-stage Liver Disease (MELD), was initiated in February 2002. Recent reports have shown that the introduction of the MELD system led to a reduction in waiting list mortality, but also that the MELD score has several limitations that call for further refinements. In the transplant community there are reasonable doubts that MELD is actually superior to the Child-Turcotte Pugh score. Therefore, the optimal liver organ allocation system is yet to be defined.