Process-managed organization has much in common with the management of the information system. Management of the company can therefore be compared to the management of the system, while it is necessary to ensure information and communication flows. Effective information processing and knowledge base building are the basis for the functioning of the organization and its strategic intent. The means to achieve this goal is the information system. Informatization is the process of penetrating ICT into all areas of society in order to make it work effectively. An important part of building the information society is eHealth. The Internet, information systems, information technology and healthcare electronisation are important aids to improve and streamline the functioning of the entire health system, as they enable faster and more effective communication between all actors in the health sector (ie pharmacies, patients, healthcare facilities and insurance companies). The aim of this paper is to analyze hospital information systems in hospitals on the territory of the Slovak Republic, to identify the modules they consist of and to define interconnections of these systems with other information systems, not only within the given organization but also from the external environment.