It is widely accepted by medical practitioners that diabetes is a major independent risk factor for the development of cardiovascular disease. However, less attention has been directed toward elevated blood glucose as a predictor of poor outcomes in hospitalized patients in cardiac critical care. This has occurred despite documentation of hyperglycemia in a significant proportion of patients admitted for cardiac care and considerable data supporting the use of intravenous (IV) insulin to achieve glycemic control. The increased risk for mortality due to hyperglycemia provides a strong rationale for an intensive approach using insulin to control blood glucose levels in cardiac patients being treated in acute care and surgical settings. IV insulin infusion is the therapy of choice for patients in cardiac critical care units, with transition to a subcutaneous insulin therapy regimen when appropriate. The timing of this transition can be critical. Strong evidence from studies on patients who have undergone cardiac surgery suggests that glycemic control by insulin infusion should be maintained for > or =3 postoperative days. Nonetheless, transition from IV to subcutaneous therapy must occur at some point during the hospital stay. In conclusion, the implementation of measures to achieve glycemic control in acute cardiac care hospital settings can significantly reduce morbidity and mortality and can substantially decrease the costs associated with prolonged hospital stays. This report reviews recent clinical data on the benefits of IV insulin infusion in cardiac patients in critical care and provides recommendations on transitioning patients from IV insulin infusion to subcutaneous therapy.