An 81-year-old man was admitted to our hospital for refractory hypoglycemia, metabolic acidosis, unexplained lymphocytosis, and significant weight loss. The patient was known to have non–insulin-dependent diabetes mellitus, hypertension, and hypothyroidism. His medications included glyburide, atenolol, and levothyroxine. He presented to his primary care physician 2 weeks prior to presentation with hypoglycemic episodes. His glyburide was stopped; however, the hypoglycemic episodes persisted.