Background: Pediatric sepsis is one of the most prevalent causes of pediatric mortalities despite all the efforts done to early predict and manage it. This study was designed to assess diagnostic and prognostic role of micro RNA-23b (miRNA-23b) in pediatric sepsis cases by assessing relation between plasma miRNA-23b expression level and results of blood culture as well as patients' outcome. Method: This case-control study included 37 clinically diagnosed sepsis cases and 18 control subjects. Assay of miRNA-23b expression was conducted using quantitative real-time PCR. Results: The expression levels of miRNA-23 were statistically significantly higher among the case group than the control group (p=0.027). Cases with negative culture witnessed statistically significant higher levels of miRNA-23b (p=0.042). For outcome, discharged cases possessed higher levels of miRNA with a statistically significant difference (p=0.002). Regarding the validity of miRNA-23b expression as a diagnostic marker for sepsis compared to blood culture results as the gold standard for diagnosis of sepsis at a cut-off value 4.08, sensitivity was (91.7%), specificity was (62%), predictive value for positive (PVP) was (73%), predictive value for negative (PVN) was (80%) with 81% accuracy. Regarding the validity of miRNA-23b expression level in prediction of outcome at a cut-off value 1.43 , sensitivity was (85.7%), specificity was (60.9%), PVP was (57.1%), PVN was (87.5%), with 70.3% accuracy. Conclusion: MiRNA-23b is a valid diagnostic and prognostic marker for pediatric sepsis. This promising marker would be used for early diagnosis and management of children with sepsis to improve their outcome.