This monograph is written based on the author's research on seismic assessment and retrofitting of corrosion-damaged reinforced concrete structures during the recent two decades. It points out that reinforcement corrosion is one of the main reasons that contribute to the deterioration of the seismic performances and durability of reinforced concrete structures. It illustrates that the mechanism of reinforcement corrosion should be investigated to propose a method for evaluating the seismic performance of corroded components and structures. It calls for a comprehensive investigation on the bond performance between corroded reinforcing bars and concrete, as well as the degradation law of seismic performance of corroded beams, columns, beam column joints, and shear walls from the perspectives of materials, components, and structures. With the promotion and application of composite materials, fiber reinforced polymer (FRP) has been proposed as an ideal material for retrofitting reinforced concrete structures. By emphasizing the mechanism of reinforcement corrosion and the integrated evaluation of materials, components, and structures, this monograph offers an idea of using FRP to retrofit the seismic performance of corroded reinforced concrete structures. It is designed as a reference work for professionals or practitioners and a textbook for undergraduates or postgraduates. This book provides valuable knowledge and useful methods that can be considered in the field of seismic assessment and retrofitting of corrosion-damaged reinforced concrete structures with other FRPs.