The benefits of tight glycaemic control (TGC) were first shown in cardiac surgical patients with diabetes. These concepts migrated to other surgical and medical specialties through intensive care units caring for a variety of patients with a variety of disease states Although some disagreement and controversy surrounds the use of TGC in the medical population, the benefits of this therapy ir the diabetes cardiac surgery population is unblemished. Perioperative hyperglycaemia has been shown to be associated with adverse surgical outcomes in several different patient populations TGC for 3 full postoperative days or more mitigates these risks Although this has been definitively proven in the diabetes coronary artery bypass graft (CABG) population, evidence for beneficia effects of TGC in other surgical populations remains elusive at this point in time. In this article, we explore the risks of hyper- and hypoglycaemia in the surgical patient; safety and efficacy of insulin protocols in the surgical population, target range goals and dura tion of therapy; the beneficial effects of TGC on decreasing mortality, reducing infectious complications, length of stay and other complications; define target surgical populations tha benefit from TGC; analyse current controversies as they relate to surgical populations; and describe questions that remain for the future of TGC.