Objective: To compare the efficiency of diagnosis of placenta accreta by grayscale ultrasound, and 3D power Doppler versus maternal level of serum alpha-fetoprotein in women with previous cesarean sections. Methods: 90 patients with previous cesarean sections after 28 weeks gestation sage divided into 2 groups; cases group with placenta previa and control group with upper segment implanted placenta. Each group will be subjected to ultrasound. Examination by greyscale ultrasound and 3D power Doppler, and maternal serum levels of alpha-fetoprotein are estimated. And the condition of placenta is determined by the surgeon intra-operatively. Results: Placenta accreta and its variants (including increta and percreta) were confirmed in 36 patients at the time of Cesarean delivery. We compared greyscale ultrasound to 3D power Doppler and MS-AFP, we found that MS-AFP was the most sensitive with 88.9 % sensitivity, followed by greyscale ultrasound with 77.8 % sensitivity followed by 3D power Doppler with 66.7 % sensitivity. However MS-AFP was the least specific with specificity of 33.3 % followed by greyscale ultrasound with 66.7 % specificity and the most specific was 3D power Doppler with 83.3 % specificity. Conclusion: MS-AFP maybe useful as a complimentary technique with ultrasound (2D and 3D) for the antenatal diagnosis of placenta accreta. It could be also used as a screening test for diagnosis of placenta accreta. KEYWORDS Placenta Accreta – Placenta previa – Ultrasound – 3D power Doppler – Alpha-fetoprotein