The essay discusses the spatial organization of advanced business services in the cities and local systems of Northern Italy, analyzing the new forms taken by economic networks with the intention of providing evidence to evaluate the research hypothesis describing Northern Italy as a fully integrated city-region, in the form of a polycentric metropolis. The analysis of the distribution and density of advanced business services in the territories of Northern Italy describes a scenario of growing specialization: not only is there a clearly defined division of competencies between production systems and urban systems, but there are also great differences in the range of services offered by cities with similar socio-economic characteristics. Cities in Northern Italy influence each other’s offer of business services: we have found indications of the presence of urban hierarchies extending beyond metropolitan and regional boundaries, across the whole of Northern Italy. This occurs not only in Milan, which emerges as the leading provider of advanced business services, but also in many smaller cities which are increasingly specializing their offers of advanced business services to fit the needs of local production chains and to stay competitive in the macro-region.