The importance of glycemic control in reducing the microvascular complications of type 1 diabetes has been clearly demonstrated with a long-term prospective, randomized interventional trial. The data are not as strong with regards to type 2 diabetes. The results of several prospective studies and one interventional study, however, all report benefits of improved glycemic indices on reducing microvascular complications. The available literature evaluating the relationship between glycemic control and macrovascular disease in type 1 and type 2 diabetes demonstrates the importance of glucose control. One could make rational scientific arguments or criticize the design and interpretations of any one individual study. Yet collectively the evidence is powerful. Additionally, there have been no negative studies reported. Lowering the glycosylated hemoglobin to less than 2 percentage points above the upper limit of normal should be the first glycemic goal for most patients with diabetes. Obviously, some patients cannot obtain this degree of control for a variety of reasons. Moreover, the intensity of therapy needs to be individualized and tailored to each patient. In addition, intensive glycemic control does not necessarily mean multiple injections or insulin pumps or home glucose monitoring 10 times a day. Intensive glycemic control means that the glycohemoglobin (hemoglobin and A1C and blood glucose values are in a normal or near-normal range, no matter how simple or how complex the treatment regimen. The most controversial issue is with regards to the relationship between hyperinsulinemia and accelerated atherosclerosis. This association is not consistently found in many of the large prospective studies, and certainly there has never been a direct cause-and-effect relationship proven. Most experts in the field recommend that insulin be reserved for patients with type II diabetes when oral therapy cannot achieve near-normal glycemic control. Weight gain and hypoglycemia are adverse effects of sulfonylurea and insulin therapy. These adverse effects are dwarfed, however, by the acute and chronic complications of poorly controlled diabetes. Lastly, estimates on the economic benefits of reducing long-term microvascular and macrovascular complications in populations are staggering. Based on the available literature, all patients with diabetes should be educated and have access to an appropriate individualized treatment regimen with the goal to normalize or near-normalize glycemic control. This should be the standard of care until proven otherwise.