Recently, studies suggested that Red Blood Cell Distribution Width (RDW) is a useful biomarker of disease in critically ill patients and an increased RDW is an independent predictor of mortality in sepsis. Evaluation of the role of RDW as a marker for diagnosis of neonatal sepsis and to correlate between RDW and other parameters of neonatal sepsis. This case control study was carried on at neonatal intensive care unit (NICU) at National Medical Institute –Damanhor. One hundred neonates were enrolled in this study, fifty neonates with neonatal sepsis either suspected or confirmed according to clinical and laboratory data and for control fifty healthy neonates with age and sex matched with the case group, all participants were investigated for CBC including (RDW, TLC, Hb, Plt, and neutrophil count), CRP and blood culture and sepsis screening. This study was conducted over a period of six month between June 2020 and November 2020. It was found that Sensitivity, specificity and accuracy of RDW CV% as a predictor of infection, it was found that at cut off value 16.2 the sensitivity was 96.0, specificity 93.0 and accuracy 95.0. Red Blood Cell Distribution Width is a cheap, readily available parameter which can be useful for predicting sepsis in neonates. Also, it can be used to predict sepsis severity as a significant difference was found between Red Blood Cell Distribution Width (RDW) value and IT ratio.