Atherosclerotic aneurysms limited to the iliac arteries are rare and entail a high risk of rupture. To evaluate the efficacy of prophylactic surgery, we retrospectively studied 15 patients (13 men and two women; mean age 69 years) treated for isolated iliac aneurysms in the Department of Cardiovascular Surgery at the University Hospital of Liège over a period of 18 years. They had a total of 25 aneurysms (20 common iliac and five internal iliac). Six patients were treated electively and nine on an emergency basis for rupture. Five of the emergency patients (33%) died in the early postoperative period (< 30 days); in each case the aneurysm had ruptured and an emergency operation was performed (55.5% mortality in the ruptured iliac aneurysm group). On the other hand, all patients treated electively survived. Our study is comparable to other recent series in the literature, which also reported a high incidence of rupture and death in emergency operations. Prophylactic elective surgery is recommended for iliac aneurysms.