The reported prevalence of established dislocation the hip in an unscreened population varies from 0.7 to 1.6 / 1000 children in European and American white populations. In clinically screened populations neonatal hip instability is reported to occur in 3 to 30 / 1000 newborns while established congenital dislocation has a prevalence of 0.1- 4/1000 of which 1/1000 is judged to be in need for surgery. Early diagnosis of DDH is essential for successful treatment and later prognosis of the disorder. Combined procedure including evaluation of both hip morphology and hip stability is currently recommended. Opinions differ about the need for universal versus selective sonographic screening for diagnosis of DDH. Currently selective screening of those infants with recognised risk factors and those with abnormal physical examination would be cost-effective and the only practicable method for most countries.