Clinical and diagnostic data were collected from 22 men with iliac artery aneurysms treated surgically over a period of 22 years. Their ages ranged from 47 to 80 years (mean 64.0). Eight patients had multiple aneurysms. Thirty isolated iliac artery aneurysms were detected, 20 aneurysms (66.6%) located on the right and 10 (33.3%) on the left side. Twenty-six aneurysms were found in the common iliac artery (86.6%). Fifteen patients were symptomatic (68.2%); rupture occurred in five patients (22.7%), three of whom were initially asymptomatic. Thirteen of 17 patients whose aneurysms did not rupture had a palpable mass (76.4%), and three had bruits in the area of the aneurysm. All 22 patients were subjected to operative procedures. Seventeen patients operated upon electively survived, whereas only three patients who were operated upon after rupture survived. Graft interposition was the most common procedure. All 20 patients who survived after the operation were followed. Two died of myocardial infarction three and five years later, one of cancer six years later, and one of an unknown cause eight years after operation. Iliac artery aneurysms are extremely rare; their diagnosis is very difficult. The mortality rate is two times higher than in aortic aneurysms, once the diagnosis has been established. Therefore elective resection and arterial reconstruction are recommended.