Background: Inflammation plays a pivotal role in the initiation and progression of atherosclerosis. Neutrophil:lymphocyte ratio (NLR) is a prognostic marker for several cardiovascular diseases, including non-ST-elevation myocardial infarction (NSTEMI). Syntax score (Sx score) is an anatomical score system for coronary artery disease (CAD) severity and can predict short-and long-term mortality in CAD intervention. Aim:To investigate the association between NLR and Sxscore as a measure of CAD severity in patients with NSTEMI. Methods:A prospective study was performed over 12 months on patients presenting with NSTEMI. Complete blood count (for NLR calculation), s. urea, s. creatinine, s. lipid profile, and s. cardiac enzymes were withdrawn upon admission. Coronary angiography with Sx score calculation was done during the index hospitalization. Results:We studied 111 consecutive patients, 85 males (76.6%) with a mean age of 55.3 ± 9.8 years. In univariate analysis, a high Sx score (≥ 33) was significantly associated withs. cholesterol, s. LDL, s. HDL, s. creatinine,s. CK, s. CK-MB, and NLR. In multivariate analysis, NLR was the only significant predictor of high Sx score [HR: 4.19 and 95% CI: 1.7-10.5, p: 0.002]. In the ROC analysis, the NLR cutoff of >7.1 had 100% sensitivity and 94% specificity to predict a high Sx score (AUC 0.97, P<0.001). We found no similar data in the literature. Conclusion:NLR is significantly associated with CAD severity in patients with NSTEMI. Admission NLR > 7.1 predicts a high Sx score with 100% sensitivity and 94% specificity, thus helping in early and better risk stratification of NSTEMI.