SUMMARYA comparative study of the amylolytic activity of four strains ofPolyporus ostreiformisled to the selection of a good amylase-producing strain. Physiological studies were carried out and under optimal fermentation conditions it produced amylase which yielded residual sugar in an average of 3.0 mg/ml by hydrolysis of starch. Several readily utilizable carbohydrates such as glucose and lactose exerted catabolic repression, inhibiting amylase induction by starch or maltose. Enzyme synthesis was maximum in logarithmic growth phase of the fungus.