Abstract : Different additives have been used to enhance the mechanical properties and durability of concrete. During the last two decades, metakaolin, has been employed to improve the mechanical properties of concrete according to the percentage of addition and replacement. Furthermore, due to the spread of metal industrial waste and its impact on environmental safety, several studies have been conducted to find the possibility of using it in construction. This can provide low cost material and save the environment. Therefore, this study aims to investigate the effect of using both metakaolin and metal industrial waste on the mechanical properties of concrete. Five concrete mixtures were designed with different metakaolin replacement rations including (0, 5, 15 and 25)%of cement weight. Also, metal strips having average width of 5 mm and average length of 30mm were added as 1% of concrete volume. Compression, tension and flexural tests were conducted on 105 specimens at different concrete ages (7, 28, and 90 days). In addition, high temperature of 600 o C was applied on specimens at 90 days to find out the effect of high temperature on the efficiency of metakaolin at late ages. The results showed the positive effect of metakaolin on concrete behavior at later ages. The optimum percentage of metakaolin was 15% to get higher compressive, tensile and flexural strengths. Moreover, adding metal waste increased concrete strengths especially tensile strength. While applying heat affected the concrete strengths negatively.