We sought to determine the early and late outcomes of endovascular versus open thoracoabdominal aortic aneurysm repair. We performed a multicenter population-based study across the province of Ontario, Canada, from 2006 to 2017. The primary end point was mortality. Secondary end points were time to first event of a composite of mortality, permanent spinal cord injury, permanent dialysis, and stroke, the individual end points of the composite, patient disposition at discharge, hospital length of stay, myocardial infarction, and secondary procedures at follow-up. A total of 664 adults undergoing surgical repair of a thoracoabdominal aortic aneurysm (endovascular: n = 303 [45.5%] vs open: n = 361 [54.5%]) were identified using an algorithm of administrative codes validated against the operative records. Propensity score matching resulted in 241 patient pairs. Endovascular repairs increased during the study and currently comprise more than 50% of total repairs. In the matched sample, open repair was associated with a higher incidence of in-hospital death (17.4% vs 10.8%, P = .04), complications (26.1% vs 17.4%, P = .02), discharge to rehabilitation facilities (18.7% vs 10.0%, P = .02), and longer length of stay (12 [7-21] vs 6 [3-13] days, P < .01). Long-term mortality was not significantly different (hazard ratio, 1.09; 95% confidence interval, 0.78-1.50), nor were the other secondary end points, with the exception of secondary procedures, which were higher in the endovascular group (hazard ratio, 2.64; 95% confidence interval, 1.54-4.55). At 8 years, overall survival was 41.3% versus 44.6% after endovascular and open repair (P = .62). Endovascular repair was associated with improved early outcomes but higher rates of secondary procedures after discharge. Long-term survival after thoracoabdominal aortic aneurysm repair is poor and independent of repair technique. Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.