EN
The major goals of the Urban Natural System identification are: preservation and conservation of the most valuable areas important for environmental performance, and ensuring proper living condition for city dwellers. In spite of key ecological functions the Urban Natural System can play also other ones like recreational, aesthetic and residential. The intensification of urbanization processes happens at the expense of Urban Natural System areas and causes deterioration of the quality of the city environment. The case study of Warsaw presented in this paper reveals the possibility of the Urban Natural System identification as the result of precisely defined environmental performance that can be used afterwords in the processes of urban development.