Abstract: In this study batch anaerobic digestion of organic fraction of municipal solid waste was carried out for 100 days at room temperature for varying substrate concentration of 115, 99 and 83g/l. The performance of reactors was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. Effect of organic solids concentration and digestion time on biogas yield was studied. The biogas yields at the end of the digestion from the reactors were 22.7L/KgVS, 54.4L/KgVS and 41.7L/KgVS respectively. About of 71.69%, 80.06% and 76.55% Volatile solid degradation were obtained during the loading in reactors.