Thirty-one patients, ranging in age from 57 to 78 years (mean 66), with the exclusion of cases with doubtful possible results, underwent abdominal aortic aneurysmectomy for asymptomatic AAA and had cultures from the aneurysmal wall and endovascular thrombus to identify possible microbiological source of future graft infection; 5 (16%) of 31 cultures yielded bacterial growth and the most common organism isolated was staphylococcus epidermidis. During an average follow-up of 15.4 months no graft infection was noted in patients with positive or negative aortic cultured. A literature review stresses the same disparity between positive cultures obtained at the aneurysmectomy and subsequent low graft-infection rate. It is concluded that the aneurysm wall itself does not represent an important source of early or late graft infection and it's suggested that the bacterial presence both in the wall and thrombus could be explained by an exogenous contamination at the operation time.