Background : TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), a material of agent orange, was reported as a deadly poison in spite of its presence at extremely small doses. It has been reported that TCDD can cause various kinds of cancers and harmful effects on humans. However, a correlation between exposure to TCDD and acute coronary syndome (ACS) including ST-elevation Myocardial Infarction (STEMI), NSTEMI and Unstable Angina is not yet known. Therfore, the aim of this study was to examine the relationship between TCDD exposure and ACS through an analysis of coronary database of the Gwangju Veterans Hospital. Methods : A consecutive 254 male patients undergoing coronary angiogram due to ACS between April 2004 and May 2009 were analysed. Included subjects were between 50 and 70 years of age. The patients were divided into two groups : 121 patients exposed TCDD (Group I, average age 60.4짹2.8 years) and 133 patients that were not exposed to TCDD (Group II, average age 60.6짹4.9 years). The clinical and coronary angiographic findings were evaluated. Results : Baseline clinical characteristics, inflammatory markers and echocardiographic parameters were not different between the two groups. The incidence of hypertension (71.1% vs 58.6%, p=0.039) and hyperlipidemia (27.3% vs 16.5%, p=0.038) were higher in patients with group I than group II. Angiographic findings such as presence of total occlusion (12.8 vs 9.4%), vessel number, lesion length, stent length, use of stent and ACC/AHA lesion classification were not different between the two groups. And, clinical parameters such as CCS angina class, pulmonary edema, cardiogenic shock were not different between the two groups. There were no statistical differences in in-hospital mortality and MACE at 12 months between two groups. Conclusion : Despite of higher incidence of hypertension and hyperlipidemia, exposure of TCDD does not affect the severity of cardiovascular disease and prognosis in the patients with ACS.