Background: Complete blood count is the most widely available laboratory test in patients with acute myocardial infarction (AMI). The usefulness of white blood cell (WBC) and hemoglobin (Hb) as prognostic predictors have been well known and that of platelet distribution width (PDW) is controversial. The aim of this study was to assess the value of the combined use of WBC, Hb and PDW in patients with AMI. Methods: This study included 1332 patients (64.0 짹 11.9 years; 901 males) with AMI. Patients were categorized into the group 0 (n=314, 26.0%), 1 (n=622, 46.7%), 2 (n=324, 24.3%), 3 (n=40, 3.0%) according to the sum of value defined by the cut-off levels of WBC (1: ���14,505/關L, 0: <14,505/關L), Hb (1: <12.65g/dL, 0: ���12.65g/dL) and PDW (1: ���51.15%, 0: <51.15%) divided by receiver-operating characteristics curve analysis. Result: The primary endpoint of in-hospital death occurred in 59 (4.4%) patients. WBC (12.7 짹 5.5/關L vs. 10.8 짹 4.0/關L, P=0.013) and PDW (54.2 짹 7.6% vs. 52.2 짹 7.4%, P=0.037) were higher and Hb (12.4 짹 2.2 g/dL vs. 13.5 짹 1.9 g/dL, P<0.001) was lower in patients with in-hospital death than in those without. There were significant differences in the in-hospital death among the group 0 (1.2%), 1 (2.7%), 2 (9.0%), and 3 (22.5%) (P<0.001) (Figure 1). In multivariate logistic regression analysis, after adjusting for multiple clinical prognostic factors, the group ���2 (odds ratio [OR] 3.800, 95% confidence interval [CI] 1.026 to 14.072, P=0.046) was an independent predictor for the in-hospital death in addition to systolic blood pressure, Killip class���3, left anterior descending infarction, log NT-ProBNP and cardiac troponin I. The group ���2 had incremental prognostic value to conventional risk factors for predicting the in-hospital death (chi-square 4.2, p=0.040). Conclusion: Combination of WBC, Hb and PDW which is a cheap and simple hematologic marker, was useful in the early risk stratification of patients with AMI.