Subclavian artery compression by a cervical rib is an uncommon but potentially disabling condition. A series of 12 patients with 15 arterial lesions is reviewed and a staging system proposed to provide guidelines for managing patients with this condition. Stage I lesions have only arterial stenosis and minor poststenotic dilatation and are managed by thoracic outlet decompression, usually consisting of cervical rib resection. Stage II lesions have intrinsic arterial damage usually with subclavian aneurysm formation and require rib resection, aneurysmectomy, and arterial reconstruction. Stage III lesions present with distal thromboembolic complications and require thrombectomy or embolectomy in addition to thoracic outlet decompression and arterial reconstruction. The anatomic and pathophysiologic bases of the syndrome are reviewed and clinical and angiographic examples of each stage are presented.