The volume of use of beds and other goods and services provided by a hospital is evidently determined by the population of the hospital area, their morbidity, the competition from other hospitals inside and outside the area and so on. When building or renovating an hospital the decision maker needs to know the present situation and, more importantly, what will happen in the future. In general, relevant information on the present situation is lacking. However, the PMSI system, established in 1985 is now operational and provides sufficient basic information on the users and their needs. The article proposes several models for predicting future trends and assessing approximatively what will be seemingly required from the hospital in 20 or 30 years from now.