A 15-year-old castrated male domestic shorthair cat presented for evaluation of polyuria/polydipsia and weight loss despite a good appetite. He weighed 9 pounds (4.1 kg) with a body condition score of 4/9. Moderate atrophy of the epaxial muscles was noted. Physical examination was otherwise unremarkable. A CBC revealed a mild, non-regenerative anemia (Hct, 25%; reference range, 31-46%).The biochemistry profile revealed hyperglycemia (glucose, 583 mg/dl; reference range, 70-120 mg/dl) and azotemia (BUN, 99 mg/dl; reference range, 15-33 mg/dl; creatinine, 3.2 mg/dl; reference range, 0.9-2.1 mg/dl). Urinalysis revealed a specific gravity of 1.015 with 4+ glucose and no proteinuria. T4 was within the reference range. A complete diet history revealed that the cat was eating ½ cup over-the-counter (OTC) dry adult maintenance cat food plus two 3 oz. cans of cat food per day (both made by good quality major manufacturers – specific varieties and flavors were included in the diet history). The cat did not receive any cat treats, table food, or dietary supplements.