Traditional concrete structures with steel reinforcing bars shall gradually deteriorate owing to external loadings and environmental attacks. Fiber reinforced polymer (FRP) is one of the most attractive alternative material for steel since it provides excellent tensile strength and much higher corrosion resistance as well as lower self-weight. This study utilized a newly developed FRP rebar that uses glass fibers in core and chopped glass fibers to make rips on the surface of rebar. Flexural test was performed on concrete beam specimens reinforced with the developed GFRP rebar at various reinforcement ratios. The stiffness of the beams reinforced with GFRP was lower than those with steel rebar. The ultimate strength, however, was improved by using the GFRP rather than the steel rebar. The rip-shaped surface provided better bonding between the GFRP rods and concrete and no significant slip/debonding was observed. In addition, the load and deflection increased gradually until the complete failure without apparent yielding. The current equations for estimating the ultimate moment was too conservative by underestimating values. However, as the reinforcement ratio increased, the difference calculated values became closer to the measured.