Objectives: Recently ischemia modified albumin(IMA) has got special attention as a diagnostic marker for myocardial ischemia. However, some previous studies have suggested that a wide variety of medical conditions other than myocardial ischemia may interfere in IMA detection in clinical practice. So this study was sought to investigate whether the IMA is useful in detecting myocardial ischemia in clinical practice. Method: We prospectively studied 500 consecutive patients (mean age 62.3 years; 317 male) with chest pain who arrived at the emergency department. The IMA levels were measured at the time of the hospital arrival in patients with chest pain within 8 hours. The electrocardiography, echocardiography, coronary angiography, or non-invasive stress tests were assessed to precise diagnosis for myocardial ischemia while blinded to the IMA results. Results: 236 patients were finally diagnosed as non-cardiac chest pain, and the other 264 patients as stable angina(3.4%), unstable angina(49.6%), myocardial infarction(39.4%) and vasospastic angina(7.6%) by coronary angiography or other non-invasive test. There was no significant difference in median IMA levels(U/ml) between the patients with non-cardiac chest pain and those with myocardial ischemia (100.5 U/ml, interquartile range 93 to 108 U/ml, vs. 99 U/ml, interquartile range 93 to 108 U/ml, P=0.361). However, there was statistically significant difference in median IMA levels between the patients with on-going symptoms irrespective of whether or not myocardial ischemia, and those without on-going symptoms (100 U/ml, interquartile range 94 to 109 U/ml, vs. 99 U/ml, interquartile range 91 to 107 U/ml, p=0.035). By log rank test, the high IMA levels were not predictive of cardiac events (p=0.3). Conclusion: This study shows that patients with on-going chest pain may have the higher IMA levels. However, it does not mean that the IMA levels can discriminate ischemic heart disease from atypical chest pain. It suggests that the various clinical conditions other than myocardial ischemia may affect the levels of IMA. Therefore, in the real clinical practice, the IMA levels may not be useful in detecting myocardial ischemia and further predicting cardiac outcomes.