Extra-anatomic bypass(EAB) is defined as bypass grafts that pass through a significantly different anatomic pathway than the natural blood vessles they replace. The two categorical reasons for doing this in aortoiliac occlusive disease are to avoid "hostile" intra-abdominal pathologic features and to avoid the high risk of transabdominal reconstruction in patients with serious visceral and systemic disease. To determine the application of this procedure, we reviewed retrospectively the characteristics and outcomes of 30 patients who underwent extra-anatomic bypasses during April, 1986 to April, 1997. Three EABs in brachiocephalic reconstruction were done including 2 carotid-subclavian bypass, 1 femoral-biaxillary bypass. 27 EABs in aortoiliac reconstruction were done including 22 femorofemoral bypass(FFB), 4 axillobifemoral bypass(AxBF). In the latter, EABs were used in older patients with medical comorbidities and contraindication to direct reconstructive procedures involving the abdominal aorta including aneurysms, graft infection, and trauma. One and five-year primary patency rates for entire EABs and FFB were 76.9%, 63.8% and 83.1%, 63.5%, respectively. In FFB, patients with limb- threatening ischemia proved to be inferior to those with claudication as measured by primary patency(p=0.013). Age(>65yr.), sex, smoking, medical comorbidities, duration of symtoms, preoperative angioplasty, use of externally supported graft did not influence primary patency in FFB. The 5-year patient survival rates for entire EABs and FFB were 70.4%, 67.9%. Limb salvage rates for entire EABs and FFB were 65.1%, 66.7% at 3 years. Our results suggest that strict selection of patients with limb-threatening ischemia and medical comorbidities may contribute inferior patency rate of EABs. To determine the application of EABs in aortoiliac reconstruction, the nature of intraabdominal pathology and operative risk with vascular surgeon's experience and judgement should be considered.