Tammy is a 10 year old, female spayed black domestic short haired cat with a 6 year history of recurrent cystitis with hematuria and crystalluria. Urinalysis reveals ammonium urate crystal formation. Surgery was performed to remove two, one centimeter, 100% ammonium acid urate stones which were radiographically evident in her bladder. Repeated laboratory tests are inconsistent with liver disease, portosystemic shunts, renal disorders, or any common cause of urate crystalluria. General considerations involving disorders of micturition are presented, with an emphasis on urate cystitis. Additionally, medical and dietary control of this problem in the feline patient is discussed.