['Endovascular repair is associated with better 30-day outcomes than open surgical repair for patients with infrarenal aortic aneurysms. In patients with complex aortic aneurysms (CAAs) requiring suprarenal or supravisceral aortic cross-clamping during open repair, few data exist directly comparing the real-world outcomes of open repair versus endovascular repair with fenestrated-branched stent grafts (FEVAR).', 'Outcomes for patients who underwent elective CAA repair using open repair and FEVAR between 2005 and 2010 were analyzed using the American College of Surgeons National Surgical Quality Improvement Program database. CAA was defined as aneurysm of the aorta involving the visceral and/or renal arteries.', 'This study compared 1091 patients who underwent open repair (group A: male, 71.5%; age, 71 ± 9 years) with 264 patients treated with FEVAR (group B: male, 82.2%; age, 74 ± 9 years). The 2 groups did not significantly differ with respect to American Society of Anesthesiologists (ASA) classification (ASA III/IV: A, 93%; B, 95%, P = 0.6), severe chronic obstructive pulmonary disease (A: 21%; B: 22%; P = 0.7), prior cardiac surgery (A: 24%; B: 20%; P = 0.19), or preoperative renal function (glomerular filtration rate: A: 69 ± 2; B: 70 ± 27; P = 0.535). Group A had significantly higher risk of any complication (A: 42%; B: 19%; P < 0.001), nonsurgical complications (A: 30%; B: 8%; P < 0.001), pulmonary complications (A: 21%; B: 2%; P < 0.001), renal complications (A: 10%; B: 1.5%; P = 0.001), and any cardiovascular complication (A: 8%; B: 2%; P < 0.001). The composite end point of surgical site infections/graft failure/bleeding transfusions were also higher in group A (A: 22%; B: 15%; P = 0.014). Thirty-day mortality was significantly lower for FEVAR (A: 5.4%; B: 0.8%; P = 0.001), as was total length of hospital stay (A: 11 ± 10 days; B: 4 ± 5 days; P < 0.001).'] Does endovascular repair with fenestrated-branched stent grafts improve 30-day outcomes for complex aortic aneurysms compared with open repair?