Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly. It is associated with early infant mortality and sudden death in adults. Traditionally, ALCAPA has been diagnosed by angiography or autopsy; however, the development of cardiac computed tomography (CT) and magnetic resonance imaging (MRI) has allowed noninvasive evaluation of the coronary anatomy by direct visualization of the origin of the left coronary artery (LCA) from the pulmonary artery. We report a case of 10-year-old girl who has been on follow up for dilated cardiomyopathy for 4 years. The definitive diagnosis of ALCAPA is reached by multislice computed tomography (MSCT). The MSCT scan showed an anomalous origin of LCA from the pulmonary trunk, with a tortuous and dilated right coronary artery and right-to-left collateralization. Consequently, the patient was successfully treated with surgery.