Numerous inherited and congenital disorders may affect the urinary system of cats. Those associated with clinical signs include renal dysplasia, renal hypoplasia, polycystic kidneys, ectopic ureters, urachal anomalies, and fistulas between the lower urinary tract and other structures. Acquired disorders of the urinary system of immature cats have been uncommonly recognized. Further studies are warranted to better define their prevalence in immature cats.