Objective: To evaluate the effect of the diameter of abdominal aortic aneurysm (AAA) on endovascular exclusion (EVE) and its results., Methods: From March 1997 to June 2007, 429 AAA patients were treated with endovascular stent-graft exclusion. According to the maximal diameter of abdominal aortic aneurysm, the patients were divided into two groups: group A (diameter < 55 mm, n = 274) and group B (diameter > or = 55 mm, n = 155). The diameter of AAA, involvement of iliac artery, length, diameter and distortion of aneurismal neck in the two groups were recorded and compared retrospectively., Results: Patients in group B were significantly older than group A (73.7 vs 71.1 years, P < 0.05). More patients in group B was complicated with coronary artery disease than those in group A (P < 0.05). The mean diameter of AAA in group A was (46.6 +/- 6.8) mm, and (66.8 +/- 11.2) mm in group B (P < 0.05). Proximal aneurysmal necks were shorter, wider and more tortuous in group B than those in group A (P < 0.05). Extraperitoneal approach, embolism of inner iliac artery and reconstruction of another inner iliac artery and stretch technique were more applied in group B. There were more endoleak during operation in group B and more stent-grafts were used. There was significant difference in morbidity rate between the two groups, while no statistic difference in mortality. And in group B, there were a high rate of endoleak and secondary intervention post operation., Conclusions: The diameter of AAA affects EVE and its results. In small aneurysms, EVE carries better outcome than in big aneurysms.