[en] OBJECTIVE: To describe the current status and the clinical data related to the effects of tight glucose control by intensive insulin therapy in critically ill patients. DESIGN: Review article. SETTING: University hospital. PATIENTS: Medical and surgical critically ill patients in whom a correlation between blood glucose and outcome variables were searched. INTERVENTIONS: Tight glucose control by intensive insulin therapy. MEASUREMENTS AND MAIN RESULTS: In contrast to the decreases in mortality and to low severity of adverse effects reported when insulin rate was titrated to keep blood glucose between 80 and 110 mg/dL, the benefits were not confirmed in multicenter prospective studies. Retrospective data found an association between a mean blood glucose level of <140-150 mg/dL and improved outcome. Currently unanswered issues include the optimal target for blood glucose, the effects of high blood glucose variability, the risks and hazards of hypoglycemia, and the potential influence of the underlying disorder on the effects of tight glucose control. CONCLUSIONS: Recommendations regarding the practical aspects of tight glucose control by intensive insulin therapy cannot be presently issued. An intermediate target level for blood glucose of 140-180 mg/dL seems to be associated with the lowest risk-to-benefit ratio.