Over the last 5 years an extended left flank retroperitoneal approach was used in 85 of 531 (16%) aortic reconstructions deemed technically complex. Abdominal aortic aneurysm repair was performed in 70 patients (82%), bypass of aortoiliac occlusive disease was performed in 11 (13%), and aortic endarterectomy for mesenteric and/or renovascular disease was performed in 4 (5%). Indications for use of this approach included a "hostile" abdomen (43 patients), juxta/suprarenal abdominal aortic aneurysm (35), large (> 10 cm) abdominal aortic aneurysm (12), extreme obesity (10), associated renal and/or visceral artery stenosis requiring endarterectomy (9), inflammatory abdominal aortic aneurysm (2), and horseshoe kidney (2). Suprarenal or supraceliac aortic clamping, averaging 31 minutes, was required in 43 patients (50%). Postoperative recovery was rapid (average length of stay, 10.2 days), and morbidity was minimal despite the complex nature of these reconstructions. The perioperative mortality rate in elective operations was 1.2%. This approach facilitated proximal abdominal aortic exposure and anastomosis, especially in large, pararenal aneurysms or in situations unfavorable to a transabdominal approach. Whereas a left flank retroperitoneal approach can be used in most aortic reconstructions, it seems especially suited to those that pose significant technical challenges.