An eighteen-year-old asymptomatic woman with a continuous murmur, normal two-dimensional echocardiogram, and mild haziness of the left lower segment of the lung on chest x-ray was diagnosed to have sequestration based on the presence of a large anomalous systemic artery arising from the descending thoracic aorta supplying the lower lobe of the left lung. Normal bronchial connections with the rest of the lung on bronchoscopy and delayed dye clearance from the left lower lobe bronchioles on bronchogram indicated its intralobar nature. The cause of the continuous murmur was thought to be the large flow through the anomalous systemic artery.