Background: The aim of this study was to investigate the role of presepsin in evaluation of severity and outcome of community –acquired pneumonia in pediatric department of Zagazig University hospitals. Method: A prospective case control study was carried out at the pediatric Department of Zagazig University Children Hospitals during the period from February 2017 to October 2017. Results: In this study, there was statistically significant difference between case and control groups in Preserpin level. Also, there was statistically significant difference in presepsin level between cases that need ICU admission and mechanical ventilation and cases treated in ward only without need for ICU admission or M.V. There was statistically significant difference in presepsin level between survivors and non-survivors. Furthermore, There was statistically significant difference in presepin level and disease severity.in which presepsin is higher in severe than moderate and mild cases. A statistically significant positive correlation between Preserpin level and granulocytes, CRP, and significant negative correlation with platelets were reported. Acutoff point of presepsin 0.8 (ng/ml) was detected for diagnosis of the community acquired pneumonia calculated from ROC curves , and the area under the curve of presepsin was 0.833 with sensitivity 97.8% and specificity 72%. Conclusion: It was concluded that Presepsin is a useful diagnostic and prognostic marker for pneumonia in Pediatrics. The present study suggests that Presepsin is a promising biomarker for reflecting the severity of Community- Acquired Pneumonia. Presepsin in combination with PRESS score may improve the predictive accuracy for severity and outcome of community acquired pneumonia in pediatrics.