Abstract: Objective To examine the mortality among the children under 5 years old in Panjin municipality of Liao-ning province from 2005 to 2015 and to provide evidences for developing intervention measures to reduce mortality in the children.Methods Vital statistics and records of death of the children under 5 years old in Panjin municipality from October 2005 to September 2015 were collected for analyses on mortality trend,cause of death and related medical treatment with SPSS 17.0.Results Totally 848 deaths of children under 5 years old were registered among 105 287 live births during the 10-year period in the region,and the mortality rate for the children under 5 years old was 8.05‰;for the 848 deaths,672(79.25%)were infants and the infant mortality rate was 6.38‰;of the infant deaths,501(74.55%)were newborns and the neonatal mortality rate was 4.76‰.The mortality for children under 5 years old,infants,and newborns showed a declined trend during the period (P<0.05).For the children under 5 years old,the mortality rate of the boys was significantly higher than that of the girls (9.07‰ vs.6.97‰) and the mortality rate of rural children was significantly higher than that of the urban children (8.89‰ vs.7.19‰)(both P<0.05).Of the 848 deaths registered,552 (65.1%),88(10.4%),and 15 (1.8%)were treated in the hospitals at provincial or municipal,county or district,and township level and 193 (22.7%)were not treated in any hospital before the death.The top five causes of death for all the deaths were premature delivery or low birth weight,congenital heart disease,birth asphyxia,other congenital anomalies,and pneumonia,accounting for 25.6%,18.4%,8.6%,8.0%,and 6.1% of all the deaths,respectively.Conclusion The mortality rate declined and the major causes of death were premature delivery or low birth weight,congenital heart disease,birth asphyxia,other congenital anomalies,and pneumonia among the children under 5 years old from 2005 to 2015 in Panjin municipality.