Ever since Benedict (1) observed that the Dalmatian dog excreted more uric acid than the non-Dalmatian dog, various investigators have attempted to detect some anomaly in the purine metabolism of this species of animal. However, no adequate explanation has been found despite the careful studies of Wells (2) and Klemperer, Trimble, and Hastings (3). Thus the liver of the Dalmatian has been found to contain apparently as much adenase, guanase, and uricase as the liver of the non-Dalmatian (2,3). As a matter of fact, these investigators concluded that no quantitative relation existed between the uric acid excretion of the Dalmatian and the uricase content of its liver. It seemed important to reinvestigate this problem. Our approach was to explore three possible causes for the occurrence of excess uric acid in the urine of the Dalmatian; namely, (1) that it was due to an accelerated total purine metabolism, (2) that it was due to a failure of the liver of the Dalmatian to convert uric acid into allantoin, or (3) that it was due to an anomaly in the kidney of the Dalmatian which allowed the more rapid escape of uric acid. The final results of our study indicated that the principal cause of the excess uric acid in the urine of the Dahnatian was the presence of a renal anomaly.