The study purpose was to present early outcomes of patients treated for thoracoabdominal aortic aneurysms or complex abdominal aortic diseases using endovascular repair with a new branched endograft. This multicenter, retrospective, observational cohort study included all patients treated with a new branched endograft. All elective patients were treated with a staged operative strategy and spinal drainage Primary outcomes of interest were technical success, early (≤30 days) mortality, and late (≥30 days) survival, and freedom from adverse aortic events. A total of 16 consecutive patients were treated for Crawford's extent type I (n = 1), type II (n = 7), type III (n = 1), and type IV (n = 5) endoleaks, with an additional two complex pararenal abdominal aortic lesions (enlarging type Ia endoleak, n = 1; anastomotic pseudoaneurysm, n = 1). There were 13 male (81%) and 3 female (19%) patients with a median age of 72.5 years (interquartile range [IQR], 69-78 years). The median diameter of the aortic aneurysm was 65 mm (IQR, 58-81 mm) and the median EuroSCORE prediction for mortality was 18% (IQR, 12%-36%). Thoracoabdominal aortic aneurysm was secondary to a previous dissection in four patients. A total of 62 of the 64 visceral vessels (96.9%) were stented. Technical success was achieved in 14 (87.5 %) and the cumulative aorta-related mortality rate was 19%. Spinal cord ischemia did not occur. The mean follow-up was 8 ± 4 months (range, 2-15 months). No type I or type III endoleaks were detected. Primary bridging stent patency was 98% (one asymptomatic thrombotic occlusion of a celiac trunk branch). No aortic reintervention was required. Endovascular repair of complex aortic aneurysms with this new branched endograft can be performed with high technical success and acceptable morbidity. A 19% mortality is quite high; however, it is tolerable in such a high-risk cohort. The survival rate was acceptable, and graft-related outcomes at early follow-up included an absence of threatening endoleaks and a high target visceral vessel patency. Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.