Introduction: Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Serum lactate is useful in predicting the prognosis of critically ill patients. Elevated blood lactate levels as well as delayed clearance have been linked to higher mortality in sepsis. Shock index is a simple and effective bedside assessment means of gauging the degree of shock and is an important predictor of identifying high-risk patients. Monitoring lactate levels may aid clinicians in understanding tissue perfusion and detecting unrecognized shock and making prompt therapy adjustments. This study aimed to find out the mean serum lactate levels in patients with sepsis presenting to the Department of Emergency Medicine of a tertiary care centre. Methods: A descriptive cross-sectional study was conducted at a tertiary care centre among the patient with sepsis presenting to the emergency department from 1 September 2022 to 30 November 2022. Ethical approval was obtained from the Institutional Review Committee of a tertiary care centre (Reference number: 26082022/02). History taking and detailed examination were done. Blood was sent for serum lactate and other parameters as proforma was sent. The shock index was calculated. Convenience sampling was done. Point estimate and 95% confidence interval were calculated. Results: Among 53 sepsis patients, the mean serum lactate level in sepsis patients was 2.84+2.02 (male: 2.83+1.70 and female: 2.85+2.42). Conclusions: The mean serum lactate level in patients with sepsis is similar as compared the studies done in similar settings.