Fifteen high-strength concrete beams were tested under concentrated load at two points to investigate their ductile behavior including flexural strength with various compressive stress distribution. Six high strength concrete beams were tested to investigate the minimum reinforcement ratios requirements for high strength concrete. Thus major test variables were the compressive strengths of concrete and tensile steel ratios. The test results were compared with flexural strength predicted by ACI 318-95. It was found that high strength concrete beams with maximum reinforcement ratio of ACI 318-95 accompany brittle failure and that compressive stress of high strength concrete beams is distributed linearly more than that of normal strength concrete beams. New maximum reinforcement ratio is proposed for the ductile behavior of high strength concrete beams.