In the ancient period, construction work was mostly carried out with help of mudstone from industry. Fly ash is a by-product of burned coal from power station and rice husk ash is the by –product of burned rice husk at higher temperature from paper plant. Considerable efforts are being taken worldwide to utilize natural waste and bye –product as supplementary cementing materials to improve the properties of cement concrete. Rice husk ash (RHA) and Fly ash (FA) is such materials. RHA is bye-product of paddy industry. Rice husk ash is a highly reactive pozzolanic material produced by controlled burning of rice husk. FA is finely divided produced by coal-fired power Station. Fly ash possesses pozzolonic properties similar to naturally occurring pozzolonic material. The detailed experimental investigation done to study the effect of partial replacement of cement with FLY ASH and RICE HUSK ASH on concrete. In this paper I started proportion form 10%(FA+RICE HUSK ASH) such as 5% FA and 5% RHA mix together in concrete by replacement of cement ,last proportion was taken 15% FA and 15%RHA, with gradual increase of fly ash and rice husk ash by 10%, 20%, 30% of partial replacement of cement . The tests on hardened concrete were destructive in nature which includes compressive test on cube for size (150 x 150 x 150 mm) at 7, 28, days of curing as per IS: 516 1959, Flexural strength on beam (100 x 100 x500 mm) at 28 days of curing as per IS: 516 1959 and split tensile strength on cylinder (150 mm ø x 300mm) at 28 days of curing as per IS: 5816 1999. It is observed that though the strength of RHA concrete goes on decreasing after the 15% addition of RHA, the composition of 20% FA + 10% RHA gives maximum strength results as well as shows the potential to be used as useful material for different building materials. Partial replacement of FA and RHA reduces the environmental effects, produces economical and eco-friendly concrete