Hyperglycemia occurs commonly in acutely and critically ill patients and has been associated with adverse clinical consequences. An emerging body of literature describes the beneficial effects of intensive glycemic monitoring and treatment (tight glycemic control, or "TGC"). This manuscript reviews the experience of a cohort of 5365 non-cardiac surgery patients admitted to the adult intensive care unit of a university-affiliated community hospital before and after implementation of TGC. Significant decreases in mortality occurred among medical and surgical patients during the TGC era, but not among trauma patients. Non-diabetics who sustained hyperglycemia had an especially high risk of mortality, and benefited greatly from treatment. Further investigations will be needed to identify the most appropriate glycemic targets for different populations of patients.