Dilated cardiomyopathy (DCM) is rarely seen secondary to Coarctation of aorta. Twenty-one months old male was referred to our hospital because of tachypnea, coughing and cardiomegaly. Echocardiography revealed most importantly CoA. Because sufficient improvement could not be acquired with interventional balloon angioplasty, he had surgical operation after one month. Coarctation of aorta should be taken into consideration in the differential diagnosis of causes of DCM in chidren. It is also so important that before we decide definitely for any patient presenting with a DCM as an idiopathic cardiomyopathy, we must rule out all possible specific causes of myocardial dysfunction. Because some of specific etiological factors of cardiomyopathies can be completely treatable, just like in our patient.