Abstract Background: Sepsis is a systemic inflammatory disorder that may be associated with higher rate of morbidity and mortality in pediatric patients admitted to intensive care unit with sepsis. Usage of different biomarker may helpful for early identification and appropriate management of sepsis. Aim of Study: To investigated the role of serum lactic dehydrogenase (LDH) in prediction of sepsis in critical pediatric patients, and its relation with prognostic scoring systems. Patients and Methods: A prospective cohort study was conducted at El Galaa Teaching Hospital between January 2020 and December 2020. A total of 168 pediatric patients were divided into the septic group (84 critically ill patients with sepsis from the pediatric intensive care unit (PICU)] and the control group (84 stable patients admitted to the in patient word). Demographic and clinical data were collected, routine laboratory investigation including LDH on admission and after 24 hours were performed. Pediatric Risk of Mortality III (PRISM III) Sequential Organ Failure Assessment (pSOFA) were assessed. Results: The serum LDH level was significantly higher in septic than control (p=0.000) and in non-survivor than survivor group (p=0.000). Also, There was statistically significant between survivor and non-survivor as regarding length of hospital stay, pSOFA score and PRISM III score. There was statistically significant positive correlation between LDH, PRISM III (r=0.842, p < 0.001) and pSOFA (r=0.785, p < 0.001). Conclusion: The study concluded that the LDH is a useful marker in predicting of sepsis in critically ill pediatric patients especially when combined with prognostic scoring systems.