Biogas is a renewable source of energy that is obtained from the anaerobic digestion of agricultural residues, animal dung, energy crops, domestic wastes and industrial wastes. These categories of waste that produce biogas are promising sources of energy and the biotechnology process of biofuel is environmentally friendly. This study aimed at modifying, fabricating and evaluating a floating drum digester. The modified floating drum digester consists of the digester tank, gas holder tank, feeding inlet pipe, gas collector outlet, slurry outlet, thermometer and hose. The gas holder tank was inserted into the digester tank while the biogas is generated in the digester tank by pressure. The biogas was produced from the mixture of cattle dung 30 % and 50 % plant wastes. Hence, the organic waste mixed with water in the ratio of 1: 2 for the digestion process. The digestion temperature was recorded daily for a period of 21 days at constant pressure of 1.32 KN/m2 throughout the experiment. The result revealed that the minimum and maximum average temperatures are 25 to 33 oC. This shows that the ambient temperature affects the temperature in the digester and the amount of gas produced is a function of the accumulated temperature in the digester. It was observed that the biogas generated increase as temperature rise. The modified floating drum digester is affordable and it is recommended for small- and large-scale production.