Background and Objectives;. Not a few of patients with syncope visit emergency room. Among cardiac causes of syncope, arrhythmias are known most common. It is The present study was aimed to examine correlation of electrolyte analysis and arrhythmia in patient with syncope who visit emergency room for the first time. Method: Retrospective study of the one thousand and ninety-seven patients with episode of syncope for the first time brought to Emergency Medical Center of Chonnam National University Hospital from July 2006 to March 2010. We reviewed standard 12-lead electrocardiogram, holter moniter, electrolyte level; sodium, potassium, calcium, ionized calcium, phosphate level at admission Results 8.6% of whole patients, ninety-six patients ( mean age 56.9 짹 16.7 years: 49 men, 47 women) experienced syncope due to arrhythmia. Fifty-two patients were diagnosed by standard 12-lead electrocardiogram, fourty-four patients were diagnosed by holter monitor. Supraventricular arrhythmia (66, 68.8%) was the most, Venticular arrhythmia (23, 24%), Conduction disturbance (7, 7.3%) following. Atrial fibrillation(37, 38.5%) was top on the arrhythmia of this study. There were no significant difference in serum sodium, potassium, calcium, ionized calcium, phosphate level But arrhythmia diagnosed by holter monitor group, potassium level was lower than standard EKG group(3.6 짹 0.5 vs 3.9 짹 0.3, P<0.05). Conclusion There was no apparent correlation electrolyte level and arrhythmia in patients with syncope. Accompanying hypokalemia could be tip for decision making applying holter monitor in patients with syncope with normal standard elecrectocardiogram.