To examine the incidence and trend of child maltreatment and its associated health problems in Hong Kong by linking healthcare and social service databases. Data on 4816 children under the age of 18 years registered with the Child Protection Registry and matching health records in public hospitals in Hong Kong from 2003 to 2010 were extracted. Associations were examined between different types of child maltreatment and child's medical diagnosis according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes including suicidal attempt (X60-X84), nonchild maltreatment related injuries (S00-S99; T00-T98, excluding T74 and T76 that are maltreatment related injuries), mental health problems (F00-F99), and congenital malformations/chromosomal abnormalities (Q00-Q99). Significant rising trends were found for child physical abuse, neglect, and sexual abuse during the period from 2003 to 2010. Psychological abuse remained stable. Risk of suicide attempt was higher among children suffering from sexual abuse, psychological abuse, and children experiencing multiple abuses; mental health diagnoses were more common in victims of psychological and multiple abuses. Congenital malformations and chromosomal abnormalities were more commonly found among neglected children. In contrast to the decreasing trend observed in the West during the study period, there has been an escalating trend in child maltreatment in Hong Kong and child maltreatment is strongly associated with major health problems. This is one of the first studies to demonstrate the power of linking healthcare and social service databases, which allows for both a better understanding of the impact of child maltreatment and as a guide future policy and service planning.