In this paper the authors apply the principles of the HOS method developed at the Faculty of Business and Management at the Brno University of Technology for evaluating the efficiency of information systems including environmental information system (EIS). Selected results of the authors´ research based on monitoring more than four hundred organizations are presented in a case study. The authors also take into account some aspects of the formulation of environmental information of the Czech Republic (supported by, e.g., the Czech Statistical Office). The primary principle of the research is to determine the level of balance of the organization’s information system, this being the key prerequisite of its effectiveness. The effectiveness is understood as maximizing the output with respect to minimizing the total cost. It is a way of implementing information and communication technologies and respecting their characteristics as properties of the information system generally and within the limits of sustainability of their development and implementation throughout their life cycle. Organizations respecting these rules support the use of the tools and state-of-the-art environmental informatics, and thus significantly contribute to their sustainable development.