Overt hypothyroidism is a rare condition that can result in severe intraoperative and postoperative complications. Preoperative detection and management is essential for safe anesthesia. If possible, surgery should be postponed until thyroid function tests normalize. We present a patient with severe untreated hypothyroidism that was detected only on preoperative anesthetic evaluation. Key diagnostic features of hypothyroidism as well as optimal preoperative management are described