This paper presents the results of experimental studies on reinforced concrete columns strengthened with carbon fiber-reinforced polymer (CFRP) composites under the combination of axial load and bending moment. A total of seven large-scale specimens with rectangular cross section ( 200 mm×300 mm ) were prepared and tested under eccentric compressive loading up to failure. The overall length of specimens with two haunched heads was 2,700 mm. Different FRP thicknesses of two, three, and five layers; fiber orientations of 0°, 45°, and 90°; and two eccentricities of 200 and 300 mm were investigated. The effects of these parameters on load-displacement and moment-curvature behaviors of the columns as well as the variation of longitudinal and transverse strains on different faces of the columns were studied. The results of the study demonstrated a significant enhancement on the performance of strengthened columns compared to unstrengthened columns.