In order to determine the flexural toughness and impact resistance of steel fiber reinforced high strength lightweight aggregate concrete(SFHLWC), a series of drop weight tests and flexural tests were carried out on high strength lightweight aggregate concrete reinforced with five different volume fraction of steel fibers 0%, 05%, 10%, 15% and 20% of concrete. For each volume fraction of fibers, the complete load deflection curves, and the numbers of blows to first visible crack as well as to failure of SFHLWC were obtained in order to determine the total energy absorbed for each specimen. The test results show that the addition of steel fibers to concrete has improved impact resistance and also the flexural toughness of SFHLWC. The test results also show that a logarithmic relation exists between toughness index and the impact energy of SFHLWC.