Background: Most infant deaths are attributed to neonatal sepsis. Reduced morbidity and mortality can be achieved with prompt diagnosis. Due to the disease's rapid course, accurate utilization of disease-specific biomarkers is crucial for timely diagnosis and treatment. Aim and objective: This study aimed to find out serum IL33 levels in neonates with sepsis and to investigate its role in the identifying of neonatal sepsis. Methods: Case-control research was performed on 45 cases diagnosed with neonatal sepsis with positive blood cultures and 45 healthy neonates as controls. A peripheral blood sample was taken from the patients and controls then IL33 levels were measured by ELISA. Results: In newborn sepsis individuals, serum IL 33 levels were significantly greater than in healthy controls (203.9±63.1vs.127.4±30.5 ng/ml, respectively: p less than 0.001). Serum IL33 levels were significantly positively correlated with CRP levels in neonatal sepsis patients. IL33 is increased in survivor than in non-survivor cases. Conclusion: Elevated levels of interleukin 33 strongly correlate with neonatal sepsis so it might function as a reliable a diagnostic indicator for neonatal sepsis.