BackgroundChildren’s congenital hip dislocation is ranked first, accounting for 49,4% among other skeletal anomalieswhich cause to physical disability.There is a tendency that the number of newborn with the congenitalhip dislocation is going to be increased in recent years, 5000:1 were in 1976 and 1000:1,3% in 1998.Bilateral dysplasia accounts for 50-62% of the total incidences. In unilateral cases,left hip seems to beinvolved 2 times more than the right,and the sex ratio is 2,5:1. Some cultures who swaddle their infantstightly with their legs straightened have a far greater incidence of developmental dysplasia of the hip. Aresearch indicated that discouraging this traditional swaddling method has reduced the prevalence ofdevelopmental dysplasia of the hip and congenital hip dislocationby 6 times in America. It is noted thatthis methodhas also been implemented in Japan and Turkey.Aim.This research aimed to study about the prevalence of congenital hip dislocation, developmental dysplasiaof the hip and other anomalies among the children who were underwent treatment at Pediatric Traumaand Orthopedic Department of National Trauma and OrthopedicResearch Centre of Mongolia in 2013-2015 and children served by outpatient visit in the clinics in 2011-2015.The following objectives were defined in the scope of the research. Herein:1. Evaluate and determine the percentage and prevalence of congenital hip dislocation anddevelopmental dysplasia of the hip among the children who undergo treatment in Pediatric Traumaand Orthopedic Departmentof National Trauma Orthopedic Research Center of Mongolia.2. Evaluate and determine the percentage and prevalence of congenital hip dislocation, developmentaldysplasia of the hip and other anomalies among children who are being served by outpatient visit inClinics of National Trauma and Orthopedic Research Center of Mongolia.Materialis and MethodThis research were studied the prevalence of congenital hip dislocation, developmental dysplasia of thehip and other anomalies among the children who were underwent treatment at Pediatric Trauma andOrthopedic Department of National Trauma and OrthopedicResearch Centre of Mongolia in 2013-2015and children served by outpatient visit in the clinics in 2011-2015.ResultTotal of 40559 inpatients underwent treatment in National Trauma andOrthopedic Research of Mongolia;of which 12217 were inpatient in Pediatric Trauma and Orthopedic Department, aged 0-19;of which1351 has been registered with birth defects of hip; of which 248 has been diagnosed with developmentaldysplasia hip, 869 with congenital hip dislocation. Sex ratio of cases of congenital hip dislocationinmales to female is around 1:4.Total of 633 (13,8%) examinations were performed in the clinics in 2011;704 (15,3%) in 2012;962 (20,9%)in 2013;1013 (22%) in 2014;1287 (28%) in 2015 respectively. It shows an increase in the number ofexaminations year by year.Total of 4142 (90,1%) cases were diagnosed with congenital hip dislocation and developmental dysplasiain both hips; left hip has been dislocated 2 times more than the right, 162 (3,5%) with congenitaldislocation of right hip; 292 (6.4%) with congenital dislocation of left hip.ConclusionTo conclude, the analysis above shows that the prevalence of developmental dysplasia of the hip andcongenital hip dislocation is still high in Mongolia. Therefore, number of diagnosis with congenital hipdislocation has rapidly increased in the recent 2 years.