Developmental dysplasia of the hip is an important but poorly understood disorder as evidenced by the vast amount of literature published to date on this topic. The precise definition of hip dysplasia is controversial and it encompasses a spectrum of abnormalities, rather than a single condition, which at one end overlap with normal hip maturation. We review the risk factors, clinical examination and radiological imaging of the hip in the infant and young child, the controversies of ultrasound screening for hip dysplasia and the current management, both operative and non-operative, of this condition according to patient age.