The experimental and analytical study was to obtain the optimal conditions for biogas generation from anaerobic digestion of rice straw using Response Surface Methodology (RSM). This experiment was carried out using 1m3 floating drum anaerobic digester. The parameters studied were temperature, pH, and substrate concentration and agitation time on biogas production from rice straw were investigated. The experimental results showed that the linear model terms of temperature, substrate concentration and the pH , agitation time had significant of individual effect (P<0.05) on biogas. The highest level of biogas produced was 0.72m3 at optimum temperature, pH, substrate concentration and agitation time of 50°c, 7.5 and 110.70 kg, 5sec respectively.