Objective To investigate the epidemiology of idiopathic scoliosis in China based on a representative sample of primary school children from Beitang district, Wuxi, Jiangsu, China. Methods All 11,024 primary school pupils from 11 schools aged 6-13 years were enrolled. A scoliometer was applied to initially screen for idiopathic scoliosis. Those angle of trunk rotation above 4° was invited to a clinical visit. Definite diagnosis was made based on a Cobb angle of 10° or above by X-ray. Inverse probability weights were used to adjust for non-attendance of the physical examination. Results 282 children (2.6%) were screened positive and 128 of them accepted clinical program. 11 children were diagnosed as idiopathic scoliosis, suggesting a prevalence rate of around 0.22% in primary school children in Wuxi. Adjusted for non-response estimated prevalence was slightly lower at 0.21%. Prevalence was higher in girls than in boys. The highest prevalence was found in girls aged 12-13 years. None confirmed case was found in children younger than 10 years old. Conclusion A relatively low overall prevalence of idiopathic scoliosis was found in primary school children of Beitang district, Wuxi. It is suggested to focus on children aged 10-13 years, while the screening for the 6-9 years olds could be slightly postponed.