The post-operative mortality and morbidity after elective surgery of a complicated (difficult) infrarenal abdominal aortic aneurysm are reported. The authors compare a group of 126 patients with a simple uncomplicated aneurysm to a group of 126 patients with a complicated aneurysm. Mortality (3.2%) is similar in both groups but the morbidity is very high in the group of patients with difficult aneurysms. The most frequent complication was renal insufficiency determined by preoperative renal insufficiency. The length of the hospital stay was much longer for the patients after a surgery for a difficult aneurysm. A preoperative correct diagnosis is always possible and the surgical technique varies according the type of anomaly. Even elective surgery of a complicated aneurysm remains a challenge.