Optimal pH for the hydrolysis of acetylglycine and diglycine by kidney extract were 7.0 and 8.0, respectively high speed crntrifugation. Thus they could be ascribed to the different enzymes: acylase and dipeptidase. By acid treatment the former was most inactivated and by heating, the latter. By a partial purification of acylase, it was enriched about 30 times, while the dipeptidase remained unchanged. Effects of various substance on the kidney acylase were examined.