There were 2 maxima for most of the preparations, one about pH 7.5 and another at about pH 9.5. Centrifugates of uricolytic extracts were quite inactive, since the residue retained most of the activity. Glycerol inactivated the uricase if high concentrations were used, and thus the use of glycerol for the preparation of uricase from tissues was undesirable. The uricolytic activity was associated with the insoluble part of the kidney tissue. A method for the preparation of uricase from kidney tissue is described.