Background: There is limited data which compared clinical outcomes of stress hyperglycemia (SH) defi ned by random glucose (RG) and fasting blood glucose (FBG). Methods: A total of 1364 non-diabetic patients whose HbA1c <6.5% in the COREAAMI (The COnvergent REgistry of cAtholic and chonnAm university for Acute MI) registry were analyzed. All enrolled patients received PCI and were divided into two groups by initial glucose level for each RG and FBG: SH and normoglycemia group (188 [RG = 180 mg/dl] and 1176 patients [RG < 180 mg/dl] by RG; and 720 [FBG = 126 mg] and 644 patients [FBG < 126 mg/dl] by FBG). The primary outcome was all-cause mortality, and we also investigated the incidence of cardiac death, nonfatal MI, any revascularization and stroke during 4 years after AMI. Results: A total of 648 patients (47.5%) were checked FBG after PCI, and remained 716 patients checked FBG before PCI. When SH was defi ned by RG, in-hospital mortality (0.7% vs. 2.7%, p=0.024), all-cause mortality (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.33-2.52, p <0.001) and cardiac mortality (HR 2.72, 95% CI 1.75-4.22, p <0.001) were higher in SH group. However, there were no signifi cant differences in in-hospital mortality (0.6% vs. 1.3%, p=0.274), all-cause mortality (HR 1.21, 95% CI 0.93-1.58, p=0.160) and cardiac mortality (HR 1.32, 95% CI 0.88-1.99, p=0.175) between SH and normoglycemia group when SH was defi ned by FBG. The incidences of nonfatal MI, any revascularization and stroke were not signifi cantly different between the groups by both RG and FBG defi nition. Conclusions: SH was associated with higher mortality compared to patients with normoglycemia in non-diabetic AMI patients when only defi ned by RG, not FBG.