Objective: To analyze the authors' midterm results (up to 4 years) using endovascular grafts to treat aortoiliac occlusive disease in patients with limb-threatening ischemia. Summary Background Data: Endovascular grafts are being used to manage some aortoiliac lesions formerly treated by aortofemoral or extraanatomic bypass grafts. However, widespread acceptance of these new grafts depends on their late patency and clinical utility. Methods: Between January 1993 and December 1997, 52 patients with aortoiliac occlusive disease were treated with endovascular grafts. The primary indication for treatment was gangrene or ulceration in 42 patients (81%) and rest pain in 10 patients (19%). Sixteen patients had symptomatic contralateral limbs that were also treated, and 27 (52%) patients required a synchronous infrainguinal bypass. Results up to 4 years were evaluated by life table analysis. Results: Forty- six (88%) of the patients had complete follow-up of 3 to 57 months (median 22 months). Six patients were lost to follow-up at a mean of 20 months after surgery. The 4-year primary and secondary patency rates for the endovascular grafts were 66.1% and 72.3% respectively. Six patients required a major amputation, and the limb salvage rate was 88.7%. Four-year patient survival was 37%, with 23 patients dying during this follow-up period. Conclusions: Endovascular grafts can often be used when conventional procedures are contraindicated or technically impractical. These grafts are a valuable alternative to extraanatomic and aortofemoral bypasses in high-risk patients with aortoiliac occlusive disease and critical ischemia.