Anerobic fermentation of organic matter — a process in the absence of atmospheric air — generates a mixture of gases: methane and carbon dioxide. The anerobic bacteria decompose the organic matter into sludge and methane, a gaseous fuel with a good calorific value. A number of organic wastes are suited to this method of methane generation: animal refuse such as cow dung, municipal and sewage wastes, vegetable wastes, human wastes and algae. Out of all these, for many a developing country with large population of cattle, cattle dung holds high promise. In this paper, I shall concentrate on the methane fuel economy based on cattle dung.