When biodegradable organic wastes decompose under anaerobic conditions, a gas mixture containing mainly methane and carbon dioxide is produced. Thus an organic complex waste that might be harmful for humans can be treated by anaerobic digestion. The gas generated by anaerobic digestion of organic wastes is called biogas. Since it contains methane, it can be burned, so it can be used as an alternative energy source. In order to design an anaerobic fermenter, micro-organism growth kinetics and substrate consuming and gas production rates should be determined. In this study, biogas production from 5 different organic solid wastes was investigated by using 6 batch laboratory fermenters. The results of the experiments were tested on the 6 different microbial kinetics indicated in the literature and the best-fitting model relating the specific growth rate of micro-organisms for each solid waste was determined by a nonlinear regression method.