Midaortic syndrome is a rare vascular anomaly characterized by coarctation of the descending thoracic and abdominal aorta. Down syndrome is associated with multiple congenital cardiac malformations but is rarely associated with developmental vascular anomalies. Midaortic syndrome may result in severe renovascular hypertension that requires early intervention to prevent life-threatening complications. We report a child with Down syndrome who presented with occlusion of the aorta and was treated with aortic bypass. More than 4 years after the procedure, the patient's renal function remains normal, and there is no evidence of recurrent hypertension. Long-term follow-up is important to assess the benefits of surgical repair.