Fibre reinforced polymer (FRP) is a composite material made of fibres possessing high strength and adhesive which binds the fibres together to fabricate the structural materials. FRP was initially developed for aircraft, ships and high-speed trains, because of the advantages like low weight and resistance to environmental factors which have been considered to be beneficial application for these producers. In 1980s, the use of FRP has been introduced to strengthen civil engineering structures .So many codal provisions have been developed by many countries. Despite further investigations are needed to understand the behaviour of FRP materials in the form of rebars in order to utilize them effectively in the construction practice. In this regard, this book highlights the main problems restricting the application of FRPs in building industry and reveals the problematic issues (related to the material properties of the FRP) important for designing RC following the formulation of targets for further research.