Background: Diagnosis of cardiac ischemia in patients attending emergency departments (ED) with symptoms of acute coronary syndromes is often difficult. Cardiac troponin is sensitive and specific for the detection of myocardial damage but may not rise during reversible myocardial ischemia. Ischemia Modified Albumin (IMA) has recently been shown to be a sensitive and early biochemical marker of ischaemia. We investigated the usefulness of IMA in patients with chest pain presenting to the ED. Method: We recruited, on a prospective sequential basis, patients who arrived at the ED with acute chest pain. The enrolment period was between November 2005 and May 2006. All enrolled patients had an ECG and blood collected within one hours of arrival, and received routine institutional care blinded to the IMA results. Standardised clinical data were collected for each patient, which included time of presentation at the ED, approximate duration of symptoms and, details of the final discharge diagnosis. We evaluated causes of chest pain by TMT, MIBI, and coronary angiography. Results: A total of 156 patients(84 men, 72 women) were recruited for the study. Mean age was 60 years (29range –89); 28(18%) were diabetic; 48 (35%) were hypertensive. Coronary angiography was carried out on 113 patients (79.4%), TMT on 9 patinets(5.8%), and MIBI on 8 patients(5.1%). Final diagnosis comfirmed by coronary angiography was unstable angina or vasospasm(37%), myocardial infarction(17.5%), and non-cardiac cause of chest pain(28 %). 28 of 156 patient were diagnosed as non-cardiac cause of chest pain by noninvasive test. IMA levels did not show stastical difference in patients with non cardiac cause of chest pain compared with acute coronary syndrome (p=0.45), compared with unstable angina or vasospastic angina(p=0.46), and in patients with unstable angina compared with myocardial infarction (p=0.23). Conclusion: IMA was not a useful marker to detect myocardial ischemia for patients with chest pain in our study. However, further prospective study of large scale have to be performed to investigate usefulness of IMA in clinical practice in future.