Abstract： Background Inflammatory abdominal aortic aneurysms (IAAAs) are rare but distinct clinical entities of atherosclerotic abdominal aortic aneurysms (aAAAs).In this study we report a 20-year single institution experience for IAAA and analyze their clinical features and long term outcome in comparison with aAAA.Methods Between 1988 and 2008, 412 cases of abdominal aortic aneurysms (AAAs) underwent elective surgical operations, 11 (2.7%) of whom were diagnosed as IAAAs and 389 (94.4%) were diagnosed as aAAAs.The former group was matched in a case control fashion to a group of 33 patients with aAAAs having similar characteristics of age, gender, and preoperative risk factors.All available clinical, pathologic, and postoperative variables were retrospectively reviewed, and the two groups were compared.Results The two groups did not differ significantly in clinical characteristics and preoperative risk factors, although patients with IAAAs were significantly more symptomatic (100% vs.42.4%, P=0.001) and had larger aneurysms on admission ((7.4±0.7) cm vs.(6.3±0.9) cm, P=0.006).In IAAAs, the preoperative erythrocyte sedimentation rate was found to be significantly elevated compared to aAAA group ((44.5±9.1) mm/h vs.(11.4±5.4) mm/h, P ＜0.05).Surgical morbidity and mortality rates did not differ between the two groups.The operation time for patients with IAAAs was significantly longer than that for patients with aAAAs ((308±36) minutes vs.(224±46) minutes, P ＜0.05), but the cross-clamp time was similar in both groups ((41.5±6.2) minutes vs.(41.8±6.2) minutes, P=0.92).A five-year survival rate analysis showed no significant difference between the two groups (P=0.711).Conclusions Despite having more symptoms, larger size and longer operation time, patients with IAAA can now be treated with approaches that cause Iow morbidity and mortality, similar to patients with aAAA.Long term outcome of IAAA patients is of no difference from aAAA patients.