In this study, the effects of initial damage of concrete columns caused by repeated cyclic compression axial loadings on the post-repair performance of reinforced concrete (RC) columns strengthened with carbon-fiber reinforced polymer (CFRP) composite were investigated experimentally. Most of the research in the world in the area of strengthening concrete columns has been performed without taking into account the preloading effects. It is normal experimental practice to apply an axial load after application of CFRP sheets on columns. In reality, preloading is the true situation when strengthening existing buildings due to service loading effects. This paper presents the results of an experimental program consisting of eleven circular RC columns tested under axial compression load to evaluate the effectiveness of CFRP confinement system to repair columns subjected to different numbers of preloading cycles. The parameters studied through this paper were number of preloading cycles, the confinement technique used to repair the columns (full or partial wrapping), and number of layers used in full wrapping. The results show that increasing number of layers in full wrapping confinement is more effective in case of increased number of preloading cycles. It was also found that partial wrapping increased ductility significantly in the case of one preloading cycle than in the case of increased number of preloading cycles.