Anomalous unilateral single pulmonary vein (AUSPV), a rare congenital anomaly, is associated with an aberrant course but normal drainage, and resembles arteriovenous malformation (AVM). We treated a 26-year-old man with AUSPV in the right lung and an anomalous segmental pulmonary vein in the left lung. CT revealed a tortuous vascular shadow with an enhancement pattern identical to that of the pulmonary vein, suggesting AUSPV. This was confirmed by pulmonary angiography. Although pulmonary AVMs were not detected on angiography, microvascular AVMs could not be excluded because delayed bubbles appeared on contrast echocardiography. A genetic examination revealed a missense mutation of BMPR2.