A 12-year-old boy with a history of recurrent aphthous ulcerations and cutaneous erythema nodosum suddenly experienced chest pain. Together, the symptoms and a positive skin pathergy test established a diagnosis of Behçet's disease. An acute extensive anterior myocardial infarction was based on electrocardiography and a cardiac computed tomography confirmed an ascending aortic aneurysm. Coronary angiography showed mural irregularity and a 50% constriction in the first diagonal artery. Following treatment with urokinase, corticosteroids, colchicine, and aspirin, most symptoms gradually improved. There were no complications noted at the one-year follow-up evaluation. Myocardial infarction is a rare event in children with Behçet's disease; treatment with corticosteroids and colchicine can result in regression of concomitant aneurysm.