Bodily injury and stress associated with surgical interventions increase glucose levels not only in individuals diagnosed with diabetes mellitus but also in patients without a preoperative diagnosis of diabetes. Whatever the cause, hyperglycemia is becoming an increasingly important indicator of perioperative patient outcomes. An elevated blood glucose level affects the body's defense systems and the body's ability to heal after surgical intervention. Perioperative nurses should closely monitor the patient's blood glucose levels and watch for signs of hyperglycemia throughout the perioperative experience. Perioperative nurses should work collaboratively with other perioperative team members to identify and treat perioperative hyperglycemia.