Chapter 112 focuses on developmental dysplasia of the hip, which includes a spectrum of abnormalities ranging from a stable hip with a mildly dysplastic acetabulum to complete hip dislocation. Pathophysiology, clinical findings, and screening studies are explored. The pathophysiology is multifactorial including mechanical, genetic and hormonal factors. Imaging strategies, findings, and treatment options are also discussed. Screening US, which is the imaging modality of choice, is performed on infants with predisposing risk factors. Outcome is quite variable with many cases resolving spontaneously without treatment whereas others stabilize with acetabular dysplasia. Treatment options include immobilization and surgery. MRI is used for problem solving in postoperative patients.