Fossil fuels are the world's major energy sources, but Widespread use of fossil fuels as an energy resource induces oil shortages, global warming and raise the cost of fuels. Production of bioethanol from lignocellulosic biomass is one way to reduce price, consumption of crude oil and environmental pollution. Rice straw and husk are globally significant sources of cellulose-rich lignocellulosic biomass and are environmental pollutants. It has been demonstrated that fuel bioethanol production from rice straw or husk in the past, but mixed rice straw and rice husk was not demonstrated. The aim of this study is to optimize acid hydrolysis conditions in bioethanol production from mixed rice straw and rice husk by 2:1 ratio respectively. Thus, process consists of the stages of pretreatment, acid hydrolysis, fermentation and separation. The reduced sugars content of hydrolyzed solutions was analyzed using DNS method and optimized by using response surface methodology (RSM) employing the central composite design (CCD). Alkaline pretreatment was obtained as effective pretreatment as analyzed by FTIR and TGA. Results collected revealed that from the mixed rice husk and straw contains 39.57% cellulose, 31.6% hemicelluloses and 18.8% lignin. Alkali pretreatment and acid hydrolysis of mixed rice husk and straw enhances cumulative fermentable sugar yield. The acid hydrolysis process variables were optimized to determine the best acid concentration (1-8%), temperature (80-130 0 C), and hydrolysis time (20-120min) that resulted in the highest glucose yield. Maximum fermentable sugar of 0.824g/l was obtained at 4.5% H2SO4 concentration, 20min time and 105 0 C temperatures. Optimum fermentable sugar of 0.81892g/l obtained at 2.39% acid concentration, 20min time and 125.12 0 C temperatures from alkali pretreated sample. The minimum yield of 0.392g/l was achieved at 8% H2SO4 acid concentration, 130 0 C temperature and 120 min time. Low levels of acid concentration, time and high temperature; it had a positive effect on the sugar yield. However, at the higher levels of all variables the yield of sugars declined, due to degradation of reducing sugar. Characterization of bioethanol product as it has PH 6.52 and 0.885 g/ml density which was comparable with bioethanol’s standard. Therefore, dilute acid hydrolysis was obtained as effective way for production of bioethanol at lower cost.