Background: There is still debate about the timing of revascularization in patients with acute non-ST-segment elevation myocardial infarction (NSTEMI). Therefore, we conducted the present study to analyze the clinical efficacy of the timing of revascularization and to test the hypothesis that an early invasive strategy is superior to an early conservative strategy for treating the NSTEMI patients. Methods: We analyzed the long-term clinical outcomes of the timing of revascularization in patients with acute NSTEMI from the Korea Acute Myocardial Infarction Registry (KAMIR). 2845 patients with acute NSTEMI (65.6 짹 12.5 years, 1,836 males) who enrolled in KAMIR were included in the present study. The therapeutic strategy of NSTEMI was categorized into early invasive treatment (within 48 hours, 65.8 짹 12.6 years, 856 males) and early conservative treatment (65.3 짹 12.1 years, 979 males). Results: There were significant differences in-hospital mortality and the incidence of major adverse cardiac events during one-year clinical follow-up between two groups (2.1 % vs. 4.8 %, p<0.001, 10.0 % vs. 13.5 %, p=0.004, respectively). According to the Thrombolysis In Myocardial Infarction (TIMI) risk score, there was no significant difference of long-term clinical outcomes in patients with low to moderate TIMI risk score, but significant difference in patients with high TIMI risk score (��� 5 points). The old age, high Killip class, low ejection fraction, high TIMI risk score, and early conservative treatment strategy are the independent predictors for the long-term clinical outcomes in patients with NSTEMI. Conclusion: An early invasive strategy improves long-term outcome of the KAMIR patients with high risk [TIMI risk score (��� 5 points)].