Background: The prognostic power of ECG changes in patients with the acute non-ST segment elevation myocardial infarction (NSTEMI) is well established. But whether it is gold standard in predicting the midterm clinical outcomes, even after the percutaneous coronary interventions (PCI) in the current era of interventional cardiology is still unknown. Methods: The study population consisted of 2,858 consecutive acute NSTEMI pts enrolled in the Korea Acute Myocardial Infarction Registry (KAMIR) study from November 2005 to June 2008. We compared the clinical outcomes of NSTEMI pts with ST-T segment changes (n=803, 28.09%) to those of pts with no changes in the in-hospital admission ECG (n=2055, 72.91%) who underwent (PCI) in the invasive arm. Results: The baseline clinical and procedural characteristics were balanced between pts with ST segment changes to those of pts without these changes except higher number of females, prior h/o of ischemic heart disease, hypertension, diabetes mellitus, current smokers, complex angiographic lesions, more usage of glycoprotein inhibitors and invasive strategy were noted in pts with ST changes. At 12 month, total deaths and cardiac deaths were higher in patients with ST-T segment change group. There was a trend toward higher total major adverse cardiac events (MACE) in the ST-T change group. However, repeat PCI, target lesion revascularization (TLR), target vessel revascularization, any re-AMI were similar between the two groups after the multivariate analysis (Table). Conclusion: ST-T ECG changes still can be gold standard prognostic marker for predicting mortality and MACE at 12 months in the acute NSTEMI setting even after the PCI.