A five day old infant underwent repair of coarctation by resection and end-to-end anastomosis of the proximal and distal segments of the arch. Four weeks later, cross-sectional Doppler echocardiography showed a tight recoarctation proximal to the origin of the left subclavian artery. A dilated proximal left subclavian artery was demonstrated, with continuous flow from it into the descending aorta. These findings were confirmed at catheterization. This “vertebral arterial steal” disappeared following transcatheter balloon angioplasty.