Systemic arterial supply to the normal basal segments of the left lower lobe is a rare congenital anomaly which has characteristic radiologic features. The lung supplied by the anomalous systemic artery has a normal bronchial tree. We recently encountered a case in which the diagnosis of systemic arterial supply to the normal basal segments of the left lower lobe was strongly suggested by the chest radiographic, CT, and MRI findings. The diagnosis was subsequently confirmed by left lower lobectomy.