AbstractBackground: Developmental Dysplasia of Hip (DDH) isthe most common congenital musculoskeletal disorder ininfants. Undiagnosed DDH result in shortening of the affectedlimb which affect the child's gait, decreasedstrength andincreased risk of degenerative joint diseases in hip and kneejoints. Hip ultrasonography provide an early diagnostic toolfor DDH. Ultrasonography can provide detailed imaging ofthe hip before femoral head ossification.Aim of Study: This study aims to highlight the role ofultrasound as a screening tool for infantile developmentaldysplasia of hip joint.Patient and Methods: 50 pediatric patients referred toMansoura University Hospital and Mansoura UniversityChildren Hospital in the period from November 2016 tillMay 2018. They were 33 females and 17 male patients withtheir ages below 6 months. The minimum age was 2 weeksand the maximum age was 18 weeks and 3 days with meanof 11.21±4.81 weeks. All patients underwent ultrasonographicexamination with measurement of Graf alpha and beta angles.Results: The present study showed that the most prevalentreferral cause is the cesarean section (44%) followed byoligohydraminos (22%) and positive family history (16%).The most detected hip type was Graf type I (52% in right hipand 50% in left hip) and the percentage of Graf type II was44% in right side and 46% in left side while Graf type III was4% in both sides.Conclusion: Ultrasonography is a good tool for assessmentthe DDH mostly in high risk cases.