Background: Neonatal sepsis is a life-threatening clinical condition. It is associated with high morbidity and mortality if not treated properly. Blood culture remains the gold standard method diagnosis of sepsis, but it takes at least 24 hours for presumptive diagnosis. Owing to the fact that neonates are vulnerable and can deteriorate easily, rapid diagnosis and management is a must. Aim of the work:Determination of the role of mean platelet volume (MPV) and plasma lactate level in the diagnosis and prognosis of neonatal bacteremia. Methods:Study included 108 clinically septic neonates aged 0-28 days. All neonates were subjected to blood culture, complete blood picture (for MPV evaluation), CRP and blood lactic acid level. Results: The current study showed that there was a significant difference between cases and controls as regards MPV, CRP, and lactate with higher mean and median values among cases with P value 0.001, 0.003, and 0.021 respectively. High blood lactic acid level was found to be highly significant in non-survived neonates when compared to the survived ones with P value 0.001. Conclusion: MPV and Blood lactic acid (BLA) tests are simple, rapid, and inexpensive methods to diagnose neonatal bacteremia. The available evidence confirms significantly higher MPV, and BLA in neonates with bacteremia compared to neonates with non-bacteremia causes of sepsis. Therefore, in clinical practice, MPV and BLA could be used as indicators for the early diagnosis of sepsis, while blood lactic acid can be used as well as a predictor of mortality.