Background: Developmental Dysplastic Hip (DDH) is common impaired development in newborns. Ultrasound (US) is the gold standard for assessing hip development in infants younger than six months. Objective: This study aimed to detect diagnostic accuracy of ultrasound examination for hip joint in neonates and to detect possible risk factors related with prevalence of DDH. Patients and methods: A total of 525 infants were referred to the Radiology Section at Zagazig University Hospitals after showing indicators of hip instability during their neonatal examinations. They were included in this cross-sectional trial. All patients were subjected to thorough history and clinical evaluation as well as US modality. Results: Of the 5,360 hip joints analyzed, 89.57% were categorized as type Ia or Ib by Graf, 10.19% as type IIa, and 0.24% as types IIc to IV. There was significant differences between clinical and sonographic assessments. A greater birth weight was found to have a negative impact on the α-angles in univariate regression analysis, as was a later delivery (by weeks) beyond the due date. Birth weight, female gender, and a family history of DDH were found to significantly affect α-angles-angles by multiple regression analysis (p<0.0001, p<0.0001, p=0.005 successively). Conclusion: There were significant differences between clinical and sonographic assessments. We also detected some possible risk factors related with prevalence of DDH. In comparison to 2D ultrasound, DDH detection with 3D ultrasound took less time and had higher inter-rater reliability.