The notion of a network is one of the key terms used to describe the contemporary world. The role of cooperation networks is also stressed in the context of innovation and its spatial aspects. In this particular case, most attention is given to metropolises as major networks of flows not only of people, capital or goods, but also of information and knowledge. The paper discusses selected spatial aspects of collaborative networks in Polish science. The discussion of examples is preceded by a theoretical introduction intended to outline various aspects of innovation networks at national and regional levels, with particular emphasis on the role of metropolises in collaborative networks.