Background/aims: Acute-on-chronic liver failure (ACLF) is a clinical entity that denotes deteriorates liver function in patients with underlying liver disease. Most studies indicate that the neutrophil-to-lymphocyte ratio (NLR). Neutrophil-to-lymphocyte ratio is a valuable prognostic marker in patients with ACLF. This study aims to assess the role of NLR ratio and evaluate the accuracy of NLR as a prognostic marker in ACLF and to compare the NLR with other standard scores. Materials and methods: This study was conducted among patients with ACLF. Neutrophil-to-lymphocyte ratio was calculated by dividing the neutrophil count by the lymphocyte count. Neutrophil-to-lymphocyte ratio was compared with AARC score, CLIF-C ACLF score, MELD-Na score, and Child-Pugh classification as a prognostic marker in ACLF. Results: A total of 109 patients were included, and the majority, (94.5%), were men with a mean age of 45 +/- 11.2 years. The NLR emerged as a valuable prognostic marker. Patients with NLR >5 demonstrated significantly higher levels of C-reactive protein (CRP), alanine aminotransferase (ALT), and CLIF-C ACLF scores, reflecting greater systemic inflammation and hepatic injury. These patients also had a higher in-hospital mortality (53.1% and 26.7%, p = 0.005). The receiver operating characteristic (ROC) analysis showed that NLR had good predictive accuracy for mortality (AUC = 0.84), supporting its utility as a simple, cost-effective tool in early risk stratification. Conclusion: With increased NLR suggesting a higher probability of death, the study emphasizes the importance of NLR as a useful prognostic biomarker in patients with ACLF. Clinical significance: Neutrophil-to-lymphocyte ratio is a prognostic marker to identify the risk of mortality in ACLF patients and helps in timely clinical decisions. Elevated NLR can help clinicians in prioritizing patients for liver transplantation.