Summary.To determine the incidence of congenital hip dislocation (CDH) a retrospective study was carried out of cases occurring in a defined population using multiple information sources. Of 138600 children born in the period 1983–1987, a total of 243 were diagnosed with CDH, defined as those requiring splintage or surgery whose treatment extended beyond 6 months of age. Incidence and estimates of relative risks for pre‐disposing factors were determined. The rate was 1.75 cases per 1000 livebirths. Major risk factors were female gender and breech presentation. The proportions of cases identified before 1,3 and 6 months of age were 8,14 and 35%, respectively. Despite using a restrictive definition, we have obtained an incidence rate among the highest reported in any United Kingdom population. Early detection is widely accepted as desirable, but neonatal screening has proved ineffect