The aim of this paper is to look at the quantitative dimension of public space resources in Polish cities, a comparative analysis of these resources, determining the share of public space in the urban spatial structure and referring this structure to European cities. The concept of ‘public space resources’ has been introduced, and is defined as those areas in the city that fulfill or can fulfill the functions of public space. This concept, and then the proposal of its operationalization, aimed to draw attention to the spatial and physical aspects of public space, which would allow to broaden and supplement social approaches in the study of public space. The quantitative approach to public space proposed in the paper also enabled a comparative research to assess the role of public space in the structure of Polish cities in a more objective manner and refer it to European cities.