Chronic shortage of ITU beds makes decisions on admission difficult and responsible. The use of computer-based mortality scoring should help in decision-making and for this purpose, a number of different scoring systems have been created; in principle, they should be easy to use, adaptable to all populations of patients and suitable for predicting the risk of mortality during both ITU and hospital stay. Most of existing scales and scoring systems were included in this review. They are frequently used in ITUs and become a necessary tool to describe ITU populations and to explain differences in mortality. As there are several pitfalls related to the interpretation of the numbers supplied by the systems, they should be used with the knowledge on the severity scoring science. Moreover, the cost and significant workload limit the use of scoring systems; in many cases an extra person has to be employed for collection and analysis of data only.