The relevant data and information is necessary for the correct decision making. It applies also in case of health system management. Nowadays, many international databases of health data are available. The first part of this paper describes databases of the most important health data providers. Databases of WHO, WHO/Europe, OECD, IARC and Eurostat are searched and compared. However, combining statistics from various databases can be dangerous because the data are mutually incomparable. This is caused by different standard population, varying definitions of similar attributes, etc. used for comparison, which complicate international data comparison. Available indicators also do not allow adequate assessment of the quality of national health systems. The last part is dedicated to projects that compare international health statistics, the quality indicators and health care expenditures in order to achieve sufficient capacity and productivity of national health systems.