The purpose of this paper is to explain clearly the role of the information system security management within the entire Port of Rijeka security process. The complexity of the Port of Rijeka system, in which the Port of Rijeka Authority contemplates the development strategy of the Rijeka traffic route and the services provided by the Port within the framework of the already existing development paradigm of the information-communication system, is elaborated. Within the management of the information-communication resources, one of the basic prerequisites for a success is the information security, or the protection of the information security management system. Therefore, the ISO 27001:2005 Certificate, which deals with the information security system management, is to be considered in the scope defined by the organization itself. While studying the advantages of the ISO 27001:2005 Certificate, the characteristics of the Port of Rijeka Authority are defined, the contents of the Certificate itself are explained and the possible comparative advantages that can be obtained within the broader framework of the port security process are stated.