Optimal fasting and postprandial glycemic control are essential to limiting microvascular and macrovascular complications associated with diabetes. Recently, stringent control of hyperglycemia in critically ill hospitalized patients with diabetes or acute hyperglycemia has been shown to reduce the risk of morbidity and mortality. This article reviews effective strategies for insulin initiation, titration, and intensification in inpatient and outpatient settings and discusses current treatment strategies when patients are being transitioned from the intensive care unit to general wards and discharged. The development of insulin analogs and premixed insulin analogs has created new options for treating inpatients and outpatients. The more physiologic time-action profiles, improved insulin delivery systems, and standardized protocols for subcutaneous insulin administration and intravenous insulin infusion have improved the safety and convenience of insulin therapy.