Percutaneous transluminal angioplasty of the subclavian artery was performed in 35 patients. In 50% of all dilations, the angioplasty balloon was inflated across the origin of the vertebral artery. No complications occurred. All subclavian steals were corrected. The relationship between the subclavian artery stenosis and the vertebral artery origin should be determined; if the vertebral artery originates from a healthy segment of the subclavian artery or from a segment with poststenotic dilatation, the angioplasty balloon can safely be distended across the vertebral artery origin.