Wheat straw or manure or both were converted to a methane-rich gas mixture. Anaerobic biomethane production is an effective process for conversion of a broad variety of lignocellulosic materials to methane to substitute natural gas and medium calorific value gases. Methane generating bacteria (methanogens) and other microbes help digest dying plants in anaerobic (without oxygen) conditions. Wheat straw wastes represent a potential energy resource if they can be properly and biologically converted to methane. The yields of methane from the materials used were found between 10.4% and 14.7%. The producing gas has an energy content of about 33%-50% of the higher heating value from the feedstock. The most important parameters for the biogas generation rates were the total solids (TS) concentration in the slurry, the digestion time, species of feeding substrate, and pH of the medium. The methane content of the biogas was in the range of 73%-79% for the runs, the remainder being principally carbon dioxide.