Objectives: Internal iliac artery (IIA) coil embolization as an adjunct to endovascular stent grafting (ESG) is common practice for treating abdominal aortic aneurysm (AAA) in patients with a substantially enlarged common iliac artery requiring extension of the stent-graft limb into the external iliac artery. The literature describing pelvic ischemia in association with IIA coil embolization contains conflicting reports of symptom severity. We studied IIA occlusion outcome as a function of coil placement in the IIA. Methods: From August 1997 to March 2002, 20 patients with AAA underwent ESG with unilateral IIA coil embolization. Coils were placed proximal to the first branch of the IIA in 8 patients and distal to the first branch in 12 patients. Symptoms of pelvic ischemia and mid-term outcome were studied. Results: Patients included 18 men and 2 women with mean age of 701/2 years (range, 53-86 years). Mean diameter of AAA was 54.4 mm (range, 38-80 mm), and of common iliac artery was 24.2 mm (range, 15-48 mm). Ten patients (50%) had new onset of symptoms of pelvic ischemia after endograft procedures: 1 of 8 patients (13%) with proximal IIA embolization had buttock claudication, and 9 of 12 patients (75%) with distal IIA embolization had pelvic ischemic symptoms, including buttock claudication in 8 and impotence in I (P = .02, Fisher exact test). No colonic ischemia occurred in this series. At 12-month follow-up, 4 patients with distal IIA embolization were symptom-free. At further follow-up to 24 months, 4 patients remained significantly limited with symptoms of claudication. Conclusions: A significantly higher incidence of symptoms of pelvic ischemia occurred with more distal placement of coils for IIA embolization. Failure to control for extent of coil placement may account for the apparently conflicting results in published studies. IIA coil embolization should be performed as proximal as possible to prevent interference with pelvic collateral circulation.