Background: Placenta previa and previous cesarean section are the two most important known risk factors for abnormally invasive placenta (AIP). AIP can be predicted as early as in the first trimester, and almost always confirmed in the second and third trimesters via Grayscale ultrasonography, with or without color Doppler has been used widely for antenatal screening and diagnosis of AIP. Objectives: To evaluate the accuracy of ultrasound in the diagnosis of placenta accreta and its variants, and to assess the impact of prenatal diagnosis in our population. Patients and Methods: A total of 60 women with placenta previa were enrolled prospectively. All those patients presented during the period of December 2017 till December 2018 to Ghamra Military and Sayed Galal Obstetrics outpatient clinic during their follow up visits in the 2nd and 3rd trimesters and underwent ultrasound examinations. Results: A number of ultrasound criteria can be used for in diagnosis of placenta accreta, as this study showing their high accuracy, they include loss of retroplacental clear zone, presence of abnormal placental lacunae, myometrial thinning, bladder wall interruption and uterovesical hypervascularity. On the other hand, both loss of retroplacental clear zone and abnormal placental lacunae could predict which patient will mostly have CS hysterectomy. Conclusion: It could be concluded that gray scale and color Doppler ultrasound have good performance in the diagnosis of AIP and that prenatal diagnosis improves maternal outcome.