Background The association of inflammatory markers with mortality in ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) remains controversial, so in the present study the relationships of high-sensitivity C-reactive protein (hs-CRP), total white blood cell (WBC) count, neutrophil (N) and lymphocyte (L) counts and the N/L ratio with occurrence of in-hospital mortality were assessed in patients with STEMI treated with primary PCI. Methods and Results Inflammatory parameters were assessed on admission in 1,078 consecutive, unselected patients with STEMI admitted for primary PCI. In-hospital death occurred in 6.3% of the patients. Of the inflammatory parameters, only hs-CRP (p< 0.001), and the WBC (p= 0.004) and N (p= 0.020) counts were predictors of death in the univariate analyses. After adjustment for other baseline clinical variables both hs-CRP and WBC count retained their independent association with mortality when analyzed both in 2 separate and in 1 multivariable models. Conclusions Both hs-CRP and the WBC count may independently of each other predict early outcomes in STEMI patients treated with primary PCI, which suggests different pathological significance of these 2 non-specific inflammatory markers in STEMI.(Circ J 2008; 72: 205-211)