Abstract: Objective: To explore the incidence of developmental dysplasia of hip (DDH) in premature infants and the role of ultrasonography in diagnosis of DDH.Methods: One hundred and nine premature infants were received ultrasonography of the hip,and the results were analyzed statistically.Results: Unstable hips were detected in 22 premature infants (20.2%) and DDH in 26 (23.9%).Among the 26 premature infants of DDH,15 had hip dysplasia,2 hip subluxation and 9 hip dislocation.The difference was significant between premature infants and normal term infants (P<0.05).The incidence of DDH was higher in infants with a gestational age of less than 34 weeks than in those with a gestational age of 34 weeks to 37 weeks (P<0.01).Conclusions: As there is a high incidence of DDH in premature infants,especially in infants with a gestational age of less than 34 weeks,it is suggested that each premature infant receives ultrasonography of the hip so that early intervention could be applied.