Background: Infant morbidity as well as mortality are frequently caused by neonatal sepsis. Neonatal sepsis can be predicted using the red cell distribution width (RDW), according to several researches. Objective: To determine if RDW can be employed as a marker for the evaluation of newborn sepsis and the assessment of its severity. Patients and Methods: 40 newborns, 20 of whom were infected and the other 20 of whom were non infected, participated in this case-control research. Patients and controls were collected from neonatal intensive care unit (NICU), Zagazig University Hospitals. Full history was taken from all participants parent, with clinical and laboratory examination were done; complete blood picture, and creatinine, blood culture, and serum level of C-reactive protein (CRP). Results: We revealed significant link between RDW and all of total leukocyte count (TLC), immature to total neutrophil ratio (I/T ratio), absolute neutrophil count (ANC), CRP, procalcitonin, severity of sepsis, and mortality. RDW and platelet count, on the other hand, have a strong negative association. With a sensitivity of 83.3 percent, specificity of 50 percent, a positive predictive value (PPV) of 71.4 percent, and a negative predictive value (NPV) of 66.7 percent, accuracy of 70 percent (p>0.05), the best RDW cutoff for diagnosing newborn sepsis severity was ≥17.9. Conclusion: Predictors of illness severity and death in newborn sepsis may be accurately predicted using baseline RDW measurements, which is critical for treatment of neonates who are at great risk of sepsis.