Abstract: Objective To investigate the prevalence of crossbite in primary dentition in children located in Changning District of Shanghai. Methods A survey of crossbite was performed in 1750 children aged from three to five years old according to the criteria for normalbite. Results Crossbite prevalence rate in primary dentition of children was 12.46% in this district. There was significant difference between boys and girls at five, while there was no significant difference between boys and girls at 3 or 4, and among all age groups. Conclusions Crossbite in primary dentition is a common oral disease. More attention should be addressed in examination, prevention and treatment.

Key words: primary dentition, crossbite, prevalence