The aim of this study was to evaluate the relation between neutrophil-to-lymphocyte ratio (NLR) and plaque components assessed by virtual histology-intravascular ultrasound in 399 coronary artery disease (CAD) patients with 471 coronary lesions. We classified the lesions into two groups according to the NLR on admission {low NLR group (NLR <= 2.73 [n=370]) vs. high NLR group (NLR > 2.73 [n=101])}. By volumetric analysis, total atheroma and the absolute necrotic core (NC) volumes were significantly greater in high NLR group (249.9 +/- 149.7 mu L vs. 192.5 +/- 127.7 mu L, P=0.001, and 32.7 +/- 26.8 mu L vs. 22.8 +/- 19.4 mu L, P=0.001, respectively) and thin-cap fibroatheroma (TCFA) was observed more frequently in high NLR group (33% vs. 18%, P=0.001). ST segment elevation myocardial infarction (odds ratio [OR], 2.159; 95% CI, 1.000-4.660, P=0.050) and NLR > 2.73 (OR, 1.848; 95% CI, 1.016-3.360, P=0.044) and total atheroma volume (OR, 1.003; 95% CI, 1.001-1.004, P=0.004) were the independent predictors of TCFA. CAD patients with high NLR had more vulnerable plaque components (greater NC-containing plaques) than those with low NLR.