Trace element selenium is an important part of the oxidative system. It was shown cardiovascular disease in selenium metabolism disorders. However there is no clear data about selenium level in patients with coronary artery disease (CAD). In this study, we investigated the hair and plasma selenium levels in patients who have severe angiographic coronary artery disease. Total 52 patients were included the study. Thirty eight patients who have severe coronary stenosis (≥50%) were included to CAD group. Control group was consisted 18 patients with normal coronary artery. Hair and plasma specimen was taken from all patients to measure selenium levels (mg/dl). Hair selenium was similar in two groups (Control group: 0.6±0.8 vs. CAD group: 0.4±1.1, p=0.2). Plasma selenium levels was higher in CAD group (Control group: 71±8, vs. CAD group: 80±6, p