Intensive animal raising in limited areas such as in Japan results in a large accumulation of animal wastes which have been causing serious pollution problems. Animal farms are bound by strict regulations to control environmental pollution, especially water pollution and offensive odor evolution. Animal wastes which are taken out from the farm are classified into 3 types; solid, slurry and waste water. Solid wastes are treated by drying or composting. Dried wastes are used not only fertilizer but also as fuel for combustion to obtain energy. Compost is the main product from animal wastes in Japan. Slurry is treated by liquid composting or methane fermentation to produce biogas. But slurry spreading to the field is almost restricted to regions such as Hokkaido where is enough space to apply a large amount of slurry. Waste water is treated by the activated sludge process to obtain clean water or simplified aeration method to produce liquid fertilizer. The most appropriate techniques of animal waste management involve proper treatment followed by application of the treated wastes to cropland for agricultural use as organic fertilizer sources.