Abstract: AIM:To investigate the association between neutrophil to lymphocyte ratio (NLR) and severity of coronary artery stenosis (CAS). METHODS: According to the results of coronary angiography, a total of 219 patients were divided into two groups according to Gensini scores: low score group (n=142) and high score group (n=77). RESULTS: NLR in acute coronary syndrome (ACS) group was higher than those in stable angina pectoris (SAP) group and NT group (P<0.05), and the NLR in high score group was higher than that in the low score group (P<0.01). A cut-off value of 2.385 for NLR predicted high Gensini score, with a sensitivity and specificity of 64% and 63%, respectively. Uni- and multivariate analyses showed that high levels of NLR, age and high-density lipoprotein were independent predictors of high Gensini score. CONCLUSION: Our study suggests that the NLR is an independent predictor of coronary heart disease and can be used to predict the severity of CAS.