In international measures, there are many information systems and networks nowadays which are accessible trough internet and support the decision-making processes. Thus, internet becomes a good opportunity to join information and public participation in the environment protection. This paper discusses the sustainable development in its relation to networking in the field of the environment protection, namely, on the basis of the internal environment analysis (SWOT analysis) and external environment analysis (PEST analysis) of the EIONET (European Information and Observation NETwork) network in Slovenia (hereafter called EIONET-SI), on the basis of which its developing strategy can be shaped. In the internal EIONET-SI analysis (SWOT analysis) from the aspects of clients, users, rivals and allies, as well as branch attractiveness was formed. Beside the SWOT analysis, external environment or PEST analysis was also performed. It treats the political, economical, social and technological EIONET-SI environment, considering computer-mediated comunications and information technology (hereafter called IT). The sustainable development aspect is presented through the development of information society as the fundamental means of enhancing the environmental awareness, empowering the society and accelerating its participation in decision-making. Results of the PEST analysis show earlier activities of the Slovenian state apparatus in the field of appropriate national strategy formation which is the condition of successful transition into the information society. Since the demand for the latter is connected to the Slovenia's accession to the EU the analysis, of which results are the issue of this article, is based on strategic EU documents. It is evident from the analysis that the key element of a successful transition is not only forming of documented national strategy, but also directing, measures and all participants' activity, considering technological and technical progress, up-to-date knowledge and strategies of developed countries. While transition into the information society does not condition only IT strategic planning in organizations, this subscription deals with wider insight and connection of formation an information society with the national economic developing strategy, too.