Abstract. Safety of big agglomerations and the issue of critical infrastructure pro-tection.A dynamic growth of big agglomerations results not only from migration of rural population to cities to find employment. The development of modern cities is favoured by the well-developed energetic, transport and telecommunication infra-structure. However, a substantial number of elements of municipal infrastructure improve the everyday life of big urban agglomerations’ inhabitants. On the one hand, this situation facilitates the development of business and on the other, it attracts more people to urban areas.The connections between the elements of given infrastructures result in emerging of new sensitive spheres in the local security systems. Some of them constitute key connections, as seen from the perspective of a given urban agglomeration. Some ele-ments of municipal infrastructure are included in the potential influencing state’s safety. Factors such as a high level of industrialization, well-developed and closely-connected nets of municipal infrastructure and anonymity being an effect of a great number of people on the given area all make it possible for new dangers to appear. Providing safety and public order in big urban agglomerations constitute a challenge both for state administration, self-governments as well as public services and guards. One of the solutions improving the level of safety and public order in the urban area is the concept of creating safe areas.The article constitutes a proposal of using the before-mentioned concept to improve safety and public order in big urban agglomerations. The articles emphasizes issued connected with critical infrastructure protection.