Hyperglycemia is common in nondiabetic patients with acute myocardial infarction (AMI). Elevated blood glucose level may reflect a response to stress, an underlying abnormal glucometabolic state or both. Regardless of mechanism, hyperglycemia complicating AMI is associated with an inflammatory and prothrombotic state, depressed myocardial contractility and increased short- and long-term mortality. Studies are needed to define optimal monitoring and management of hyperglycemia in nondiabetic patients with AMI.