Carbon fiber with high strength, light weight, and high durability has been used for the seismic rehabilitation and strengthening of a number of existing reinforced concrete structures. The authors have been investigating the seismic retrofitting methods using carbon fiber and those effects for improvement of earthquake resistance capacity since 1984. We have developed three types of seismic retrofitting methods, namely for building columns, chimneys, and bridge columns. After the 1995 Great Hanshin-Awaji Earthquake Disaster, the amount of seismic retrofitting work using CFRP has significantly increased. This paper consists of 7 sections: Section 2 introduces carbon fiber used and the product forms; Sections 3 through 6 describe the seismic retrofitting methods by CFRP; Section 3 is an overview of the methods; Section 4 describes construction procedure of retrofitting; Section 5 gives an outline of research and development; and Section 6 discusses utilization and construction records.