Renal dysfunction can be a prohibitive risk for open repair of complex thoracoabdominal aortic aneurysms (TAAAs) and pararenal aortic aneurysms (PRAAs). However, the effect of renal dysfunction from fenestrated and branched endovascular aneurysm repair (FB-EVAR) on outcomes is poorly defined. Our objective was to review the association of renal function on patient survival after FB-EVAR. The present study reviewed the clinical data of consecutive patients enrolled in a prospective nonrandomized study to investigate FB-EVAR for PRAAs and TAAAs at a single institution with 1 year of follow-up (2013-2017). The patients were categorized by preoperative chronic kidney disease (CKD) classification, and the early- and long-term mortality was assessed. During the study period, 231 patients had undergone FB-EVAR for 80 PRAAs, 89 type I-III TAAAs, and 62 type IV TAAAs. The mean age was 74.6 ± 6.7 years, and 71% were men. Of the 231 patients, 126 had had CKD stage 1-2, 96 CKD stage 3, and 9 CKD stage 4-5 (all with baseline creatinine >2.0 mg/dL). Patients with CKD stage 4-5 had demographic data similar to those with normal renal function but had had slightly larger aneurysms (6.5 vs 7 cm; P = .15). The 30-day mortality was 0.5% (n = 1) for those with CKD 1-3 vs 0% for those with CKD 4-5 (P = .73). The 1- and 3-year survival analysis showed no major hazards (95% vs 88% and 84% vs 75%, respectively; log-rank P = .98) between the CKD 1-3 and CKD 4-5 groups. The median follow-up period was 2.6 years (interquartile range, 1.5-3.7 years). Two patients with CKD 4-5 had died during the follow-up period. Although a small sample size for evaluation, selected patients with CKD 4-5 might have similar short- and long-term mortality compared with those with normal to moderate renal dysfunction after FB-EVAR. Although a major contraindication for open repair, renal dysfunction might not be as prohibitive for endovascular repair in well-selected patients. Copyright © 2020 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.