The study focuses on the compressive strength, split tensile strength, flexural strength performance of the sisal fibre concrete containing a different percentage of slag as a partial replacement of OPC. The cement in concrete is replaced accordingly with the percentage of 10%, 20% and 30% by weight of slag. And 1% of sisal fibre is added to the concrete. Concrete cubes are tested at the age of 7,14 and 28 days of curing. Finally, the strong performance of slag used fibre reinforced concrete is compared with the performance of conventional concrete. From the experimental investigations, it has been observed that the optimum replacement of Ground Granulated Blast Furnace Slag powder to cement is 20% for M 30 grade. Addition of sisal fibre in the concrete mix significantly influenced the cracking behavior and ultimate strength of beams. Addition of 1% sisal fibre in the RC beams increases both the flexural first cracking strength and flexural toughness of the SFRC beams and leads to an appreciable increase in their ductility and stiffness compared to those conventional RC beams without the addition of sisal fibre.