There is increasing evidence that aggressive glycemic control for patients admitted into the hospital improves clinical outcomes, especially for patients with cardiovascular disease. There appear to be a variety of mechanisms for this. Although hyperglycemia has been shown to result in poor wound healing and more infectious complications, especially after cardiac surgical procedures, what has become clear is that the treatment of hyperglycemia with i.v. glucose, insulin, and potassium (GIK) results in better clinical outcomes even in patients without diabetes. The mechanisms for this are not year clear, but could be related to the insulin administration, perhaps due to suppression of various cytokines or free fatty acids. The practical use of insulin in these patients requires basic understanding of the use of both i.v. and s.c. insulin. Although there are several appropriate options for both of these routes of administration, it is critical that all caregivers involved in this population's care are knowledgeable about insulin strategies.