Recently, stress hyperglycemia, occurring in the vast majority of critically ill patients, has become a major therapeutic target in the intensive care unit (ICU). Stress associated with critical illness induces the release of counter-regulatory hormones. In addition, several clinical interventions, such as administration of cortico-steroids, enteral or parenteral nutrition, or dialysis, further predispose patients to hyperglycemia. Moreover, in critical illness, changes in carbohydrate metabolism occur resulting in insulin resistance and relative insulin deficiency.