This study evaluated outcomes of open and endovascular repair (EVAR) of internal iliac artery (ILA) aneurysms (IIAAs) with or without preservation of IIA flow. 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 (hip claudication, ischemic colitis, and spinal cord injury). There were 64 patients (57 men, 7 women) with mean age of 73 years (range, 52-90 years). Seventy-eight IIAAs (36 unilateral and 28 bilateral) were treated. Fifty-five patients (86%) had elective repair (mean size, 3.0 ± 1.2 cm) and nine (14%) required emergent repair (mean size, 6.7 ± 2.4; range, 3.6-10 cm). Open repair in 48 patients (75%; 43 elective, 5 emergent) included IIA bypass in 38 or endoaneurysmorrhaphy in 10, combined with aortoiliac reconstruction in 40. EVAR in 16 patients (25%; 12 elective, 4 emergent) required IIA coil embolization in 11, iliac branch device in three, or IIA bypass in two, combined with bifurcated aortic stent grafts in eight. Early mortality was 1.8% for elective (1 of 43 open, 0 of 12 endovascular) and 11% for emergent repair (1 of 5 open, 0 of 4 endovascular; P = NS). Early morbidity and length of stay were significantly (P < .05) higher for open repair (39%, mean 9.7 ± 4.3 days) than for EVAR (12%; mean 4 ± 4.8 days). Pelvic ischemic complications occurred in 11 patients (17%), including hip claudication in eight, ischemic colitis in two, paraplegia in one. Pelvic ischemic complications occurred in 11 patients (25%) who had exclusion of at least one IIA, and in none of the patients with bilateral IIA preservation (P < .03). There was no difference in pelvic ischemic complications for elective (16%) vs emergent repair (22%) nor for open repair (13%) vs EVAR (24%). After a mean follow-up of 2.4 years, primary and secondary patency rates of IIAA bypasses were 95%. Freedom from pelvic ischemic complications at 2 years was 100% for patients with two patent IIAs and 75% ± 8% for those who had at least one IIA excluded (P = .05). Endovascular repair of IIAAs is associated with fewer complications and shorter hospital stay than with open repair. Patency of IIA bypasses is excellent. Patients who had preservation of IIA flow with bypass or iliac branch device developed no pelvic ischemic symptoms.