Background: The most prevalent infection in cirrhotic individuals is spontaneous bacterial peritonitis (SBP). Acute GI bleeding, a history of SBP, or low ascetic fluid protein contents are all risk factors for the development of SBP in cirrhotic individuals. The purpose of this study was to see if the neutrophil-tolymphocyte ratio (NLR) could predict spontaneous bacterial peritonitis in individuals with liver cirrhosis. Patients and methods: This prospective, casecontrol and observational study was conducted at Internal Medicine Department, Zagazig University Hospitals during the period from June 2021 to March 2022. The study included 100 cirrhotic patients. The patients were divided into two groups: Group I included 50 cirrhotic patients with SBP (case group) and group II included 50 cirrhotic patients without SBP (control group). Neutrophil to lymphocyte ratio was calculated for all patients. Results: In this study, there was statistically significant difference between the two studied groups in neutrophil count, lymphocyte count and increased neutrophil to lymphocyte ratio (group 1 had increased neutrophils and decreased lymphocytes than group 2). Conclusion: We can conclude the clinical utility of NLR as a biomarker predictive factor in the occurrence of spontaneous bacterial peritonitis (SBP) .