Abstract: In this paper we present the potential for small and medium sized enterprises grouped in industrial areas or parks for systemic eco-innovation through industrial symbiosis strategies. The study was carried out in an industrialised region in the self-governing region of Cantabria (Northern Spain), which comprises 161 inventoried firms, located in 9 different industrial areas. By sectors, 40% work in commerce, the repair of motor vehicles, motorbikes and motorcycles and personal and domestic articles, 16% in metallurgy and the manufacture of metallic products, 13% in construction and the remaining 31% work in such diverse sectors as real estate services, the paper industry, food and the chemical industry, among others. The information on resources and waste flows was collected by means of programmed visits, with a success rate of 104/161 enterprises. The preliminary results show opportunities both for substituting resources with waste products in real and virtual cases and for sharing waste management services and infrastructures. The diversity of synergetic opportunities is related to the number of enterprises that participate in each industrial area and with the occurrence of the types of waste products in the global system; thus we find options for action on different systemic levels. An optimistic scenario for escalating industrial symbiosis between small and medium sized enterprises is revealed from the project, thanks to both the companies' current behaviour and to the potential opportunities that were detected. This paper establishes the basis for advancing in subsequent stages of quantification and the evaluation of the feasibility of specific alternatives for turning the system under study into an industrial ecosystem.