Over the last three decades, one of the most important issues in economic geography and regional development, which have occurred in the background of industrial clusters, is concerned with understanding factors such as social, economic and spatial characteristics based on social capital, social networks, trust and proximity. Increasing interest in clusters has focused on issues such as how these factors will be the role of evolution within industrial clusters. In this paper, non-economic factors behind the evolution of industrial clusters in Turkey have been discussed through social networks. The aim of this article is to determine the role of social networks on evolution of innovation in industrial clusters. In this context, the main hypothesis about the source of social networks and innovation is that social networks have a decisive influence on the changing of innovation activities through formal and informal linkages having out-cluster and intra-cluster of Ankara and Konya machinery engineering firms. The data used in the study were obtained by in-depth interviews and surveys conducted on sample clusters. It has been verified that social networks are determinants of innovation, although the social networking potentials of the clusters are different.