Hyperglycemia is very common in critical care and is the focus of intense clinical research. To date, more than 24,000 patients have been enrolled in interventional randomized trials. The pioneering studies by the Louvain group reported remarkable benefits of intensive insulin therapy in intensive care units; however, subsequent large multicenter trials failed to confirm these findings. Recent evidence suggests that pre-admission glycemic status should be taken into account in defining glucose targets, through new parameters such as the stress hyperglycemia ratio and relative hypoglycemia, which include pre-admission glycemic control. Continuous glucose monitoring and individualization of glycemic targets according to these new parameters and the patient’s clinical context are likely to bring major advances in the management of hyperglycemia in critically ill patients.