Chaotic atrial tachycardia is usually seen associated with chronic obstructive pulmonary disease in adult patients. It is a rare arrhythmia problem in pediatric and infantile patients. Tachyarrhythmia may present with dilated cardiomyopathy in infancy. We diagnosed chaotic atrial tachycardia in a 2.5-month old patient admitted with dilated cardiomyopathy. Sotalol 3.5 mg/kg in combination with digoxin was started and the dosage was increased to 7.5 mg/kg in accordance with the heart rate. Cardiomyopathy had resolved in two months and the rhythm reverted to sinus in five months. We did not observe any side effects.