This research aims to utilize recycled rice straw and rice husk to produce environmentally friendly concrete with optimum properties. An experimental program was conducted which consisted of three phases. Rice straw and rice husk were treated by different methods to obtain rice straw ash (RSA), rice husk ash (RHA) and rice straw (RS) which were used as partial cement replacement in concrete mixes. Chemical treatment was made for rice straw and the test results showed that this treatment managed to produce pure silica without emission of carbon monoxide. Concrete mixes containing RS were exposed to high temperatures of 300°C, 500°C and 700°C for 1 and 2 hours. Fresh and hardened concrete tests were made to investigate the effect of cement replacement with different percentages of RS, RSA and RHA on concrete properties at normal and elevated temperatures. The obtained test results demonstrated the improvement of physical and mechanical properties of concrete, especially at high temperatures.