A six-year-old castrated male domestic shorthair cat was presented to the Emergency Service at Cornell University Hospital for Animals with an approximate twelve-hour history of stranguria and vocalization when attempting to urinate. On presentation the patient had a large turgid urinary bladder that was difficult to express and he was painful on caudal abdominal palpation. Obstructive feline lower urinary tract disease (FLUTD) was diagnosed and the patient unblocked, the urinary bladder lavaged, and an indwelling urinary catheter secured in place. During hospitalization in the intensive care unit (I CU) the patient was treated with intravenous Plasmalye-A (120 ml/kg/hr), buprenorphine (0.01 mg/kg orally every eight hours), amitriptyline (1.6 mg/kg orally every twelve hours), and phenoxybenzamine (0.32 mg/kg orally every twelve hours). Abdominal radiographs, a complete blood count, blood chemistry, and a urinalysis were performed and no definitive cause for the urinary obstruction was identified. A presumptive diagnosis of feline idiopathic cystitis (FIC) was diagnosed at this time. After 2 days of hospitalization, the patient was discharged to the care of his owners with buprenorphine, amitriptyline, and phenoxybenzamine. Instructions for environmental and behavioral modifications that can be made to reduce the risk for subsequent recurrences ofFIC were also given to his owner.