Objective To evaluate outcomes of open (OR) and endovascular repair (II-EVAR) of internal iliac artery aneurysms (IIAAs) with or without preservation of internal iliac artery (IIA) flow. Methods We reviewed the clinical data of consecutive patients treated for IIAAs between 2001 and 2012. End-points were morbidity, mortality, graft patency, and freedom from pelvic ischemic symptoms (buttock claudication, ischemic colitis, and spinal cord injury). Results There were 97 patients, 87 male and 10 female, with mean age of 74 ± 8 years. A total of 125 IIAAs (71 unilateral and 27 bilateral) with mean diameter of 3.6 ± 2 cm were treated. Eighty-two patients (86%) had elective repair and 15 (14%) required emergent repair (mean size, 6.7 ± 2.4 cm; range, 3.6-10 cm). OR in 60 patients (62%; 49 elective, 11 emergent) included IIA bypass in 36 (60%) patients and endoaneurysmorrhaphy in 24 (40%). II-EVAR in 37 patients (38%; 30 elective, 4 emergent) required IIA embolization in 29, iliac branch device in five or open IIA bypass in three, combined with bifurcated aortic stent grafts in 17. Early mortality was 1% for elective (1/49 open, 0/33 endovascular) and 7% for emergent repair (1/11 open, 0/4 endovascular). Early morbidity (43% vs 8%; P <.001) and length of stay (9 vs 1 day; P <.001) were significantly higher for OR as compared with II-EVAR. Pelvic ischemic complications occurred in 25 patients (26%), including hip claudication in 23, ischemic colitis in two, and paraplegia in one. Freedom from buttock claudication at 2 years was 25% in patients with no IIA preserved, 68% with preservation of one, and 95% with preservation of both IIAs (P =.002). Freedom from buttock claudication was higher after OR than after II-EVAR (79% vs 59%; P =.05). Primary and secondary patency rates of IIAA bypasses were 95%, and 80% at 1 and 3 years, respectively. Conclusions II-EVAR of IIAAs is associated with fewer complications and shorter hospital stay compared with OR. Open and endovascular IIA reconstructions have very good long-term patency, and preservation of IIA flow is associated with higher freedom from buttock claudication.