Even in the age of extensive aortic replacement special circumstances may warrant the insertion of extraanatomic thoracic aortic bypass grafts. Our experience with 17 patients is analyzed. Between 1988 and 1994, ten female and seven male patients (mean age 37.5 years, range 9-69 years) were treated for the following indications: (1) complex CoA (n = 5); (2) reoperation for CoA (n = 6); (3) extensive aortic occlusive disease (n = 4); and (4) complicated aneurysm (n = 2). Routing of the grafts was: ascending-descending aorta (8); ascending-abdominal aorta (4); left subdavian artery- descending aorta (2); descending-descending aorta (2); and descending-abdominal aorta (1). Eight procedures were reoperations. In four patients concomitant cardiac operations were performed: one aortic valve replacement, one patch plasty of the LCA, and two composite graft replacements of aortic valve and ascending aorta, one of them with CABG. Three early deaths occurred. two after emergency operation in thoracic aneurysm under dire conditions (one perforation, one infection), one after ascending-abdominal aortic grafting with multiple branch revascularization. The underlying pathology was relieved successfully in all 14 survivors. In the two patients with concomitant aortic valve and isthmic stenosis, critical anterior motion of the mitral valve, presumably because of the massive afterload reduction of the left ventricle, complicated the perioperative course. One patient was reoperated because of aneurysm 4 years after descending-descending aortic grafting for complex CoA with poststenotic dilatation. In complex aortic coarctation or hypoplasia extraanatomic bypass grafts are expedient and effective procedures, especially for reoperation. Their use in the treatment of aneurysmal lesions remains an exception.