Background: preeclampsia (PE) is a pregnancy-specific multisystem disorder that is characterized by development of hypertension and proteinuria with or without body edema after twenty weeks of gestation, resolving by 6-12 weeks postpartum in previous normotensive women. Objectives: comparing complete blood count (CBC) parameters especially Mean platelet volume (MPV), in pre-eclamptic and normal pregnant women in the third trimester of pregnancy and to evaluate whether this parameter has a prognostic significance in determining the severity of preeclampsia. Methods: The study was conducted at alhussein university hospital. It included 150 pregnant women. They were assigned to 2 groups: 1st group: 34 pregnant women with preeclampsia, and 2nd group: 116 normal pregnant women free of any medical disorders Results: The current study showed no statistically significant difference between PE compared to normal pregnancy (with p-value >0.05 NS). Conclusions: we have found that MPV values do not have any determining effect on the presence of preeclampsia. Recommendation: The results of this study recommend that MPV has no prognostic significance in determining preeclampsia, although large-scale clinical studies and longitudinal study of platelet size changes through gestations are still awaited and fixing methods and methods used for an automated blood count.