Introduction: Acute cholecystitis accounts for most of the hospital admissions related to gastrointestinal diseases. In approximately 90% of patients, inflammation develops due to obstruction of the cystic duct by one or more gall-tones. Delayed management can lead to increased morbidity, due to progression to severe cholecystitis, such as gangrenous change, abscess formation, and gallbladder perforation. The Neutrophil-to-Lymphocyte ratio is derived from the counts of circulating neutrophils and lymphocytes, both of which are major leukocyte subpopulations. The inflammation-triggered release of arachidonic acid metabolites and platelet-activating factors results in neutrophilia, and cortisol-induced stress results in relative lymphopenia, and thus, the Neutrophil-to-Lymphocyte ratio accurately represents the underlying inflammatory process. Objectives: 1. To evaluate the utility of the Neutrophil-to-Lymphocyte ratio (NLR) as a prognostic indicator in patients with cholecystitis 2. To identify a relevant NLR value that discriminates between simple and severe cholecystitis. Materials and methods: A retrospective analysis of patient data compiled by assessment of operative findings documented and patient follow up recorded over the period encompassing ten years (2019-2010) at Kusuma Hospital, Kakinada. Results: Our study population comprised of 359 patients with simple cholecystitis (69.63%) and 109 patients with severe cholecystitis (30.36%). The NLR of 3.0 could predict severe cholecystitis with 70.5% sensitivity and 70.0% specificity. A higher NLR (≥3.0) was significantly associated with older age (p =0.001), male gender (p =0.001), admission via the emergency department (p <0.001), longer operation time (p <0.001), higher incidence of postoperative complications (p =0.056), and prolonged length of hospital stay (LOS) (p <0.001). Conclusion: NLR ≥3.0 was significantly associated with severe cholecystitis and prolonged LOS in patients undergoing cholecystectomy. Therefore, preoperative NLR in patients undergoing cholecystitis due to cholecystitis seemed to be a useful surrogate marker for severe cholecystitis.