With the convergence of information and communication technology (ICT) industries in the mobile communication sectors, new actors have started emerging such as mobile contents and media service industries. The traditional distribution of power in ICT industries of mobile communication sectors has significantly changed based on relations with the new actors. Recently, the concept of a “mobile ecosystem” which embraces this environmental shift is highlighted. The traditional industries such as hardware and network-based firms and new ICT industries such as software and service-based firms grow up simultaneously creating the mobile ecosystem. In this respect, this study aims to explore ecological indexes for identifying roles of ICT industries in the mobile ecosystem. To be specific, the ecological indexes are proposed to take new roles and position of ICT industries in the perspective of ecosystem into account. For this, the inter-industry analysis, which includes the physical flows between industries, is mainly used since the ecosystem is operated by streamlining physical flows. First, the mobile ecosystem is structured by using physical input-output flows and industrial relationships. Second, to explore roles of ICT industries in the mobile ecosystem, four ecological indexes have been developed and combined based on the result of inter-industry analysis: productivity, size, spillover effect, and coverage. As a result, we identified six roles for ICT industries and their relationships: commodity, landlord, controller, keystone, facilitator, and dominator. Regarding these ecological roles and relationships in ICT industries, strategic and policy implications are also suggested to improve the health of the mobile ecosystem.