Cardiovascular complications constitute the major cause of morbidity and mortality in patients with diabetes. The Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) provided consistent evidence that intensive glycemic control prevents the development and progression of microvascular complications in patients with type 1 or type 2 diabetes. However, whether intensive glucose lowering also prevents macrovascular disease and major cardiovascular events remains unclear. Extended follow-up of participants in these studies demonstrated that intensive glycemic control reduced the long-term incidence of myocardial infarction and death from cardiovascular disease. By contrast, the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial, and Veterans Affairs Diabetes Trial (VADT) results suggested that intensive glycemic control to near normoglycemia had either no, or potentially even a detrimental, effect on cardiovascular outcomes. This article discusses the effects of intensive glycemic control on cardiovascular disease, and examines key differences in the design of these trials that might have contributed to their disparate findings. Recommendations from the current joint ADA, AHA, and ACCF position statement on intensive glycemic control and prevention of cardiovascular disease are highlighted.