Inappropriate management of organic wastes can cause serious damage to the environment by polluting water and air, which can lower the quality of life. Ammonia and greenhouse gases (CH4 and CO2) emitted from the waste storage units can pollute the air. Inappropriate application of nitrogen and phosphorus on fields as manure can lead to eutrophication of surface water resources and pollution of soil and ground water. Conversion of the organic wastes to biogas through anaerobic digestion will, however, reduce the adverse impact on the environment and will contribute to a reduction in the consumption of fossil fuels. This study investigated the anaerobic digestion of broiler manure and greenhouse waste as well as anaerobic co-digestion of broiler manure and dewatered and non-dewatered wastewater treatment plant sludge for the production of biogas. To this purpose, biochemical methane potential experiments were performed. Moreover, the effects of nutrient and trace metal supplementation on the biogas yield were also examined. The results of this study indicated that (1) The obtained biogas values for broiler manure and greenhouse waste were very well in agreement with relevant literature values and comparable to that of food waste reported in the literature, respectively. (2) The experimental biogas production observed for co-digestion of broiler manure and dewatered and non-dewatered wastewater treatment plant sludge is higher than literature values.