Reusing Agro product waste by utilizing them into building materials is a moderate solution to achieve a sustainable environment. Date Seed (DS) and Tamarind Seed (TS) are lightweight when compare with another concrete ingredients. It reduces the self-weight of the structure. This Study reports that study on mechanical properties of the utilization of date and tamarind seed as a partial replacement for fine aggregate. They are washed, dried, and grained to make medium sand size. The mixes were prepared by weight basis of 10 % to 20 % of date seed and 1.5 % to 2.5 % of tamarind seed for M sand in M25 grade concrete mixes. For each mix, the standard size of cubes, cylinders, and prisms as per Indian standard was cast and tested to assess the mechanical properties such as compressive, split tensile and flexural strength. The results of this investigation indicated that the replacement of 10% of DS and 1.5% of TS with fine aggregates achieve closer to the strength of Control Concrete (CC) and further replacement shall reduce the concrete strength.