Electrocardiographic criteria for the diagnosis of cardiac ischemia in adults are well defined; however, analogous criteria for the diagnosis of cardiac ischemia in infants and children remain ambiguous. The difficulty in defining electrocardiographic criteria in pediatrics relates to age-dependent differences in the pediatric electrocardiogram, the presence or absence of congenital heart disease, and multiple and diverse etiologies of myocardial injury that lead to an ischemic pattern on the electrocardiogram. In this report, we illustrate 3 pediatric cases in which the electrocardiogram met adult diagnostic criteria for acute transmural myocardial infarction, without coronary artery abnormalities in 2 cases and with a transient coronary abnormality in the third. In conclusion, ST-segment changes diagnostic of transmural myocardial infarction in adults may be seen in pediatric patients in the absence of coronary artery occlusion.