This thesis focusses on the treatment of glucose in patients in the perioperative period. In part I current treatment of patients with diabetes in the perioperative period in Dutch hospitals is discussed. Furthermore, we describe the difference in perioperative glucose control between patients with type 1 and type 2 diabetes mellitus. Finally we report the ineffectiveness of metformin continuation to improve perioperative glucose control. Part II revolves around the use of incretin mimetics, specifically GLP-1 as an alternative to insulin for perioperative glucose control. We describe a systematic review of studies on incretin therapy in perioperative and intensive care. Furthermore, the GLOBE trail is described. This was a multicentre study on the effectiveness of a GLP-1 receptor agonist to improve perioperative glucose control in cardiac surgery patients. We found that Liraglutide reduced the need of insulin and improved perioperative glucose levels. A secondary analysis also revealed improved postoperative cardiac function in the patients using Liraglutide.