The prognosis of uncorrected aortic coarctation is poor due to development of heart failure. We performed an on-pump beating heart extraanatomical ascending-descending aortic bypass using a beating heart positioner in an adult with coarctation complicated by severe left ventricular hypertrophy. A 51-year-old woman was referred with severe hypertension. Computed tomography demonstrated severe distal aortic arch narrowing. Coarctation of the aorta was diagnosed. A posterior pericardial beating heart extraanatomical bypass via median sternotomy was performed from the ascending to descending aorta using a heart positioner. Her postoperative course was uneventful and blood pressure was normal on a low-dose beta-blocker.