The predictive value of leukocyte counts has been reported in patients with acute myocardial infarction (AMI). We aimed to evaluate the predictive value of the total leukocyte count and neutrophil-lymphocyte (N/L) ratio for mortality due to AMI. A total of 522 patients with acute ST-elevated MI were included in the study. The study population was divided into tertiles based on admission N/L ratio values. High (n = 174) and low N/L (n = 348) ratio groups were defined as patients having values in the third tertile (> 5.77) and lower 2 tertiles (<= 5.77), respectively. The high N/L ratio group had a significantly higher incidence of in-hospital cardiovascular mortality (13.8% vs 4.6%, P <.001). An N/L ratio > 5.77 was found to be an independent predictor of in-hospital cardiovascular mortality (hazard ratio: 3.78, 95% confidence interval: 1.71-8.30, P =.001). A high N/L ratio is a strong and independent predictor of in-hospital cardiovascular mortality of AMI with ST elevation.