The aim of this study was the chemical analysis of organic wastes in terms of their use as feedstocks for methane fermentation. The study included wastes such as turkey manure, solid sludge from the sewage treatment plant Hajdów, the substrate after the mushrooms growth and the materials obtained after squeezing liquid or drying fermentation residues, as well as charcoal derived from biomass biogasing pyrolysis. The tested materials were analysed for the content of organic carbon and copper, lead, cadmium, manganese and calcium. It was found that the amounts of organic carbon and metals in the investigated wastes were varied. The turkey manure was characterised by the highest content of organic carbon. Noticeable content of lead was found in turkey droppings and in the sediment from Hajdow. Significant amount of iron appeared in the sediment from Hajdów.