Background: Hypertensive disorders in pregnancy, especially preeclampsia are among the commonest medical disorders encountered in pregnancy and major contributors to maternal & fetal morbidity and mortality. Objective: Assessment of the efficacy of 3^rd trimester three-dimensional power Doppler (3D PD) ultrasound of placental volume and vascular indices in determining the severity of preeclampsia. Subjects and Methods: A cross-sectional analytic study involving 200 women from 18 to 35 years old, with singleton pregnancies in the third trimester complicated with preeclampsia. The subjects were further divided into two groups of 100 patients stratified by disease severity; severe group and non-severe group. Results: The non-severe and severe preeclamptic groups had a significant decrease in placental volume. No significant correlation was found between gestational age and placental volume regarding severity of preeclampsia. The non-severe group had significantly higher values for each of the 3 indices: Vascularization index (VI), Flow index (FI), and Vascularization Flow index (VFI) (16.9 versus 8.5), (36 versus 26), and (4.9 versus 2.6), respectively, compared to the severe group. Both the non-severe and the severe groups had a significant negative correlation between gestational age (GA) and VFI. Additionally, neither the severe nor the non-severe groups showed any correlation between VI and GA, while FI showed a non-significant inverse correlation with GA. Conclusion: The 3D Power Doppler ultrasound may provide alternative methods for assessment of placental blood flow and provide insights on pathophysiology of placental disease. Additional studies are required for verification of its accuracy and applicability in clinical practice.