Metropolitan areas occupy an increasingly important place in national strategic documents. The delimitation of metropolitan areas, i.e. determining their territorial range and thus the number of inhabitants, is one of the most controversial issues regarding the metropolis. In Poland, there is no single officially accepted concept of defining a metropolitan area. The metropolitan area is not only the very center of the metropolis – i.e. its highly urbanized cities and districts, but the entire functional area, which is a system of interdependent activities in the field of production, exchange, consumption and administration. The article presents selected classifications of metropolitan areas in Poland and characterizes 12 selected areas based on cities associated in the Union of Polish Metropolises.