In terms of contemporary civilization development one of the key aspects of environmental protection is the effort to avoid wasting resources. In the case of environmental information systems there is a necessity to strive for such systems, which deliver the highest benefits with the lowest possible consumption of resources (material, energy, as well as human, etc.). Therefore, every information system must be regarded comprehensively, i.e. as a set of mutually interactive subsystems (components, parts). The experiences confirm that the information system, parts of which are not mutually balanced, leads to the lower effectiveness and efficiency of the system as a whole in contrast with a system which may be managed in such a way that all its parts are maintained at a comparable level. Thus, the effectiveness of environmental/information systems must be harmonized as a whole. This paper presents “the HOS method” developed in the Faculty of Business and Management of the Brno University of Technology. This method enables the primary assessment of the balance of organizations’ information systems. The HOS analysis is based on a considering of the basic subsystems: Hardware, Orgware and Software (hence the title HOS), but also the following subsystems: Peopleware, Dataware, Customers, Suppliers and Information System Management. The understandable and transparent HOS diagrams for assessing the balance of an information system are presented in a short case study where authors submit also some selected statistics about their current survey results obtained by means of empirical measurement of approximately four hundred chosen organizations from the Czech Republic and Slovak republic. The research is realized using the Zefis portal.