Cardiac beriberi is caused by thiamine deficiency. Shoshin beriberi is a rare and fulminant form of cardiac beriberi characterized by hypotension, high output heart failure, lactic acidosis and anuria. Without early recognition and immediate treatment, most of these patients will be fatal. Therefore clinical diagnosis of shoshin beriberi is most important in emergency situation. We report a case of shoshin beriberi with clinical features mimicking acute coronary syndrome. Fifty year old male patient with chronic alcoholism was presented with shock, hypoxia, right heart failure and severe acidosis. Electrocardiogram showed abnormal Q in V1-3 and mild ST elevation and level of troponin I was slightly elevated. All manifestations including lactic acidosis were dramatically subsided in 18 hours by thiamine infusion. Even in developed country, shoshin beriberi can be occurred in patients with malnutrition and/or chronic alcoholism and should be differentiated with acute coronary syndrome.