Persistent 5th aortic arch (PFA) is a rare congenital cardiac anomaly that was firstly reported by Van Praagh et al, in 1969. A 3-month-old boy was referred to us with no symptom but heart murmur. Cardiac echocardiography and the following 3-dimensional computed tomography (3D-CT) scan revealed PFA with coarctation of aorta. There was pressure gradient of 50 mmHg between upper and lower limbs. He was carefully observed at the outpatient clinic because of no afterload mismatch. At the age of 9 months, coarctectomy and end-to-end anastomosis was performed between the PFA and distal arch below left vertebral artery. A histological examination of resected tissue revealed the thickened intima and rough elastic fiber that is absolutely different from normal aorta. Careful observation is necessary with the possibility of future aneurysmal change or re-coarctation, although the postoperative course has been so far uneventful.