Introduction:The presence of ACE Insertion/Deletion polymorphism is proposed to be associated with a higher risk for abdominal aortic aneurysm. The aim of this study was to examine a relationship between the occurrence of I/D polymorphism among patients with ascending aortic aneurysm and bicuspid or tricuspid aortic valve structure. Material and method:In this case-control study, 360 patients divided into two groups: 1) patients with ascending aortic aneurysm and bicuspid or tricuspid aortic valve (n= 175), and 2) those without ascending aortic aneurysm as control samples (n=185). The presence of copy number variant (CNV) patterns (Insert/Deletion) of ACE gene was analyzed using real-time polymerase chain reaction. Results:The frequency of the CNV normal pattern (wild genotype) of ACE gene, among the patient with ascending aortic aneurysm with bicuspid and tricuspid aortic valve and control group was 25.4%, 30.2%, and 34.6% respectively. The frequency of CNV loss pattern among the three groups was 59.3%, 41.4%, and 49.7% respectively, while the frequency of CNV gain among those groups was 15.3%, 28.4%, and 15.7% with no statistically signifi cant difference between aneurysm group and control (P-value = 0.117). The frequency of CNV loss genotype among case group with bicuspid aortic valve was signifi cantly higher than tricuspid aortic valve aneurysm group. (P-value =0.031).Conclusion: CNV pattern of ACE gene is not a predicting factor for occurrence of ascending aortic aneurysm with or without bicuspid aorta. However, there seems to exist a correlation between CNV loss and bicuspid aorta.