Objective: Failure of infrarenal endovascular aneurysm repair (EVAR) due to loss of proximal seal is increasingly common. Open surgical conversion can be challenging and has been associated with significant morbidity and mortality. The aim of this study was to evaluate the use of fenestrated-branched EVAR (F/BEVAR) for the treatment of patients with prior EVAR failure. Methods: Consecutive patients enrolled as part of the Aortic Research Consortium in six prospective, nonrandomized, physician-sponsored investigational device exemption studies evaluating F/BEVAR between 2012 and 2018 were included in this study. The cohort was stratified according to whether the F/BEVAR procedure was performed after EVAR failure. Demographics, operative details, perioperative complications, and length of stay were compared between groups. Postprocedural survival, type I or type III endoleak, target artery patency, target artery instability, and reintervention rates were calculated using Kaplan-Meier method and compared between groups. Results: A total of 893 patients underwent F/BEVAR; 161 (18%) were treated after failed EVAR and 732 (82%) were treated without prior EVAR. Patients with failed EVAR were more often men (84% vs 66%; P <.01) with larger aneurysms (6.9 cm vs 6.4 cm; P <.01). There were no differences in aneurysm extent (P =.20) between groups; for the entire cohort, there were 19% juxtarenal, 9.2% suprarenal, and 72% thoracoabdominal aneurysms. The average number of targeted arteries per patient was 3.6 in both groups. The procedural technical success (99% vs 97%; P =.15) did not differ between groups, but radiation dose (4750 vs 2920 mGy; P =.02), dose-area product (154,572 vs 82,842 mGy·cm2; P <.01), and operative time (5.2 vs 4.6 hours; P <.01) were significantly higher in the failed EVAR group. Median intensive care unit length of stay (2.9 days) and total length of stay (6.3 days) did not differ between groups. The 30-day mortality rate (failed EVAR, 2.5%; no EVAR, 1.1%; P =.25) and 30-day major adverse event rates did not differ between groups. Kaplan-Meier estimates of freedom from type I or type III endoleak (91.9% vs 92.5%; P =.65), target artery patency (97.3% vs 97.0%; P =.91), freedom from target artery instability (86.3% vs 88.8%; P =.53), and freedom from reintervention at 1 year (84.7% vs 88.7%; P =.10) did not differ between the failed EVAR and no EVAR groups, respectively. One-year survival was decreased in the failed EVAR group (86.3% vs 91.9%; P =.02), but this effect did not persist on multivariable analysis (hazard ratio, 1.52; 95% confidence interval, 0.88-2.62; P =.14). Conclusions: In this multicenter study, F/BEVAR was safe and effective in patients with prior failed EVAR, with nearly identical outcomes to those of patients without prior EVAR. However, differences in procedural metrics indicate higher level of technical challenge in performing F/BEVAR in patients with prior failed EVAR.