Background & Objective: Developmental dislocation of hip (DDH) as an inherited joint disorder results from external location of the head of femora from the acetabulum.Early diagnosis of this disorder is very important and any delay may result in long life handicap. Nowadays new methods such as sonogrphy are recommended in diagnosis of this disorder. Radiology and physical examination are traditional methods. This study was designed to evaluate the results of sonographical, radiological and physical examination findings in 100 infants who were suspected to have DDH.

 Methods: This analytical-cross sectional study was done in private clinics from June 2004 to June 2005. The one hundred infants who were suspected to have DDH in physical examination entered the study. A questionnaire was completed for each infant, and then sonography and radioghray have been done for them. The data were collected and analyzed by statistical programs.

 Results: Among 100 infants 48% were female and 52% male, with mean age 42±7.23.In 44% they were the firstborn.58% had normal delivery and 42% cesarean section. 15% had breech presentation. In 28% radiological and 56% sonographical methods showed findings in favor of DDH.

 Conclusion: This study showed, simultaneous physical and sonographic examination especially during the first month result in early and precise diagnosis of DDH, on the other hand it does not have radiologic side effects.