The purpose of this study was to examine the fate of aneurysmal iliac arteries managed during endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).We analyzed data from the Cook Zenith trial. Follow-up was at 1 month, 6 months, 12 months, and then annually for 5 years. Patients were evaluated according to the largest iliac artery diameter: group A (≥ 20 mm) and group B (< 20 mm). These groups were further subdivided based on iliac artery growth ≥ 5 mm during follow-up. The Fisher exact test and χ(2) test were used.Of 736 patients treated, 671 had a follow-up examination (group A = 274). In group A, 220 (80%) were treated with flared limbs in the common iliac artery. Group A did not demonstrate increased iliac growth as compared to group B. Furthermore, both groups had a similar percentage of patients that experienced iliac artery expansion of 32.1% and 31.5%, respectively. Extension to the external iliac artery did not affect growth (P = .4). No difference was noted in the need for secondary interventions between groups. However, group A patients that did not experience growth were more likely to develop a distal type I endoleak than group B patients who did not develop growth (P = .03). There was no difference in serious adverse events (SAEs) between groups (P = .51). However, patients that developed iliac artery growth in either group were less likely to have an SAE compared to patients who did not experience growth (P = .035). There was no difference in the mean percent oversizing of the iliac limbs between groups A and B. However, the mean percent oversizing in groups A and B that had iliac artery growth was significantly higher than in those that demonstrated no growth (P < .01).Aneurysmal iliac arteries managed by flared limbs or external iliac extensions at the time of EVAR for AAA do not demonstrate future iliac growth, increased rate of secondary interventions, or SAEs compared to patients with normal iliac arteries. This suggests that aneurysmal iliac arteries can be safely treated with appropriately sized limbs landed in the common or external iliac artery.