Hyperglycemia is common and associated with markedly increased mortality rates in patients hospitalized with acute coronary syndromes (ACS). Despite the fact that several studies have documented this association, hyperglycemia remains underappreciated as a risk factor, and it is frequently untreated in ACS patients. This is in large part due to limitations of prior studies, and the remaining critical gaps in our understanding of the relationship between hyperglycemia and poor outcomes. The main objective of the present statement is to summarize the current state of knowledge regarding the association between elevated glucose and patient outcomes in ACS and to outline the most important knowledge gaps in this field. These gaps include the need to specifically define hyperglycemia, develop optimal ways of measuring and tracking glucose values during ACS hospitalization, and better understand the physiological mechanisms responsible for poor outcomes associated with hyperglycemia. The most important issue, however, is whether elevated glucose is a direct mediator of adverse outcomes in ACS patients or just a marker of greater disease severity. Given the marked increase in short- and long-term mortality associated with hyperglycemia, there is an urgent need for definitive large randomized trials to determine whether treatment strategies aimed at glucose control will improve patient outcomes and to define specific glucose treatment targets. Although firm guidelines will need to await completion of these clinical trials, the present statement also provides consensus recommendations for hyperglycemia management in patients with ACS on the basis of the available data.