The overall aim of this chapter is to identify the current state-of-the-art of our knowledge of the relationship between infrastructure and productivity. The chapter focuses on two particular forms of infrastructure, namely, transport infrastructure and digital/broadband infrastructure. The chapter reviews the long-standing debate about the links between transport infrastructure and the economy, and the recent debates about the impacts of transport infrastructure on economic agglomeration, which are seen as being key to productivity enhancement. The more limited research base on digital connectivity is also examined. The chapter also addresses the issue of the level of productivity within the infrastructure sector.