The coarctation involving the aortic isthmus, with hypoplasia of the upper aortic segment, was satisfactorily repaired in a 15-year-old girl. The technique used was subclavian flap arterioplasty followed by reimplantation of the distal subclavian artery into the left carotid artery. Suprisingly weak femoral pulses were noted postoperatively and prompted a control angiogram. This showed an intraluminal diaphragm 2 cm below the site of the previous repair, with a 100 mm Hg gradient. At reoperation, a centrally performed fibrous diaphragm was excised, and the aorta was enlarged with a small Dacron patch. The postoperative course was uneventful.