Abstract: Objective To investigate the predictive value of neutrophil/lymphocyte ratio (NLR) in new-onset heart failure in elderly patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) without revascularization therapy. Methods A total of 164 elderly patients with acute NSTEMI without revascularization were enrolled and their basic information and laboratory examination results were retrospectively analyzed. According to the presence of new heart failure, they were divided into two groups. Both groups were compared for clinical characteristics. Logistic regression analysis was performed to analyze the influence factors of new heart failure occurs. A ROC curve was plotted to evaluate predictive value. Results The incidence of new heart failure in elderly patients with acute NSTEMI without revascularization was 53.66%. The new heart failure group presented a remarkably higher NLR than those without heart failure(P<0.05). Multivariate Logistic regression analysis showed that NLR was an independent risk factor for new-onset heart failure in elderly patients with acute NSTEMI without revascularization (HR=1.158, 95%CI:1.040-1.290, P=0.008). The area under the ROC curve was 0.780 (95%CI: 0.706-0.855, P<0.01), with an optimal cutoff of 5.98, a sensitivity of 71.2% and a specificity of 76.2%. Conclusions NLR can be used as a predictor of new heart failure in elderly patients with NSTEMI without revascularization therapy.