There is growing evidence that control of hyperglycemia in the critically ill patient improves outcome. Normalizing blood glucose levels decreases the risk of developing sepsis, end-organ damage, and hospital mortality. Critical care clinicians must be familiar with current and benchmark research supporting control of hyperglycemia and use this knowledge to ensure appropriate application of evidence-based practice for decreasing or preventing complications in the critically ill patient. This article describes the effects of hyperglycemia and discusses the evidence supporting tight glycemic control in such patients. The necessary steps to implement an intensive insulin therapy protocol for control of acute hyperglycemia are detailed.