A substantial number of patients being evaluated or treated for cardiovascular disease are found to have glucometabolic disorders. Identification of such patients is important because treatment for coronary artery disease and stroke needs to be individualized. Hyperglycemia on admission or during hospitalization regardless of whether diabetes mellitus is known to exist in these patients is associated with increased morbidity and mortality. Despite the fact that this has been known for some time, various strategies to reduce hyperglycemia have had mixed results in cardiac outcomes. Another important factor is that a new diagnosis of diabetes mellitus in these patients should result in the patient's triage to appropriate healthcare professionals to optimize glycemic control. The prevalence of hyperglycemia in patients admitted with acute cardiovascular disease and the effect of hyperglycemia on outcome are reviewed.