Backgrounds: Carbon monoxide (CO) is common chemical asphyxiant that causes tissue hypoxia with prominent neurologic and cardiovascular injury. Cardiac toxicity of CO poisoning can be presented as two clinical patterns. One is transient global left ventricular (LV) dysfunction and the other is LV dysfunction with regional wall motion abnormalities. We analyzed the frequency and patterns of the cardiac toxicity in the patients with consecutive CO exposure. Materials and Methods: We included total patients with intentional CO exposure in the emergency room. We analyzed their clinical and echocardiographic patterns. Results: From January 2009 to June 2009, we included total seven patients with intentional CO exposure. Of them, four showed transient global LV systolic dysfunction, especially in patients with severe CO poisoning, pulmonary edema and high concentration of troponin I level. They showed complete recovery of LV systolic function with conventional treatment after 2~7 days (Table). Conclusion: CO poisoning can cause transient LV dysfunction. With increased incidence of intentional exposure to CO, the presence of cardiac toxicity should be identified with echocardiographic examination.