Background: 3D power Doppler ultrasonography enables the quantitative analysis of the region observed through vascular indices as VI (vascularization index), FI (flow index) and VFI (vascularization flow index), which show the quantity of vessels, the local blood flow and their combination and placental volume. These indices can be calculated using VOCAL program. Aim of the Study:  This study aimed at comparing placental volume and vascular indices using 3D ultrasonography and 3D power Doppler in pregestational diabetic and non-diabetic pregnant women at the first trimester (11^th week and 13^th week). Patients and Methods:  This current study was conducted at Antenatal care Clinic in cooperation with "the feto-maternal Unit for ultrasound assessment", Ain-Shams University Maternity Hospital during the period between November 2015 and April 2017, on 46 women at the eleventh 11^th week and thirteen 13^th week of gestation.  They were divided into two groups: Group (A) included 23 women with pregestational diabetes mellitus and group (B) included 23 non-diabetic pregnant women as a control group after respecting certain inclusion and exclusion criteria. Results: There was no statistically significant difference between pregestational diabetic and non - diabetic group as regard placental volume and vascular indices (VI, FI and VFI). Conclusion:   There was no statistically significant difference as regard placental volume and vascular indices (FI,VI and VFI) in pregestational diabetic compared to non-diabetic pregnant patients at the first trimester of pregnancy especially with good glycemic control but changes may be present with poor glycaemic control.  Recommendations: Further studies are recommend as regard evaluating placental volume and vascular indices (FI,VI and VFI) in pregestational diabetic at the second and the third trimester of pregnancy giving more time for the pathological effect of diabetes mellitus to appear.