Recently, many research were performed to develop the high strength concrete and reinforcing bar because super tall building and large space structures require the high strength structural materials. The purpose of this paper is to evaluate the flexural performance of reinforced beams with high strength concrete and high strength reinforcing bars. Total 9 simple beam specimens divided by 3 groups tested for evaluating the flexural performance. Main test variables were concrete compressive strength from 27 to 68MPa and yield strength of longitudinal reinforcement from 400 to 700MPa. Test data analyzed in the viewpoint of cracking load, ultimate flexural strength, load-deflection relationship, crack progress, failure aspects and ductility. Test results indicate that flexural capacity of the specimen is similar from a standpoint of unit strength-area of reinforcement regardless concrete compressive strength. Flexural stiffness of the specimens with high strength reinforcing bars were reduced, and this phenomenon is well agreed with the reduction of effective moment of inertia $I_e$. But stiffness reduction ratio was decreased when concrete compressive strength increase. Number of crack was decreased and maximum crack width was increased when concrete compressive strength increase.