Activated sludge from the actual plants was used to treat industrial wastes rich in carbohydrate, in order to determine the capacity of sludge to accumulate polysaccharide and the role of such accumulation in the removal of carbohydrate from the wastes. The capacity to accumulate reserve polysaccharide was relatively high for sludges treating wastes with a high ratio of carbohydrate BOD to toal BOD, such as confectionery, fruit juice and soft drink wastes. With wastes having a relatively low percentage of carbohydrate BOD, such as kraft pulp, yeast culture and brewery wastes, the capacity to accumulate reserve polysaccharide was lower than that of the former sludges, even though the wastes contained a relatively large amount of carbohydrate. The sludges with the high capacity to accumulate polysaccharide also showed a high initial rate of glucose removal, although a definite realtionship was not observed between the activity of the sludges to remove glucose and the respiratory activity with glucose.