Abstract: A cross sectional survey was carried out among children aged under 7 years in seven cities of Jiangsu province in order to obtain the prevalence of cerebral palsy and to explore the association between twinning and cerebral palsy. The prevalence of childhood cerebral palsy in twins was 9.74‰(95% confidence interval 6 15‰ to 13 33‰),being 6.4 times that in singletons (95% confidence inteval, 4.4～9.3). When stratified by birthweight, the prevalence of CP in twins with low birth weight was lower than that in singletons at the same biHh weight group. In contrast, in normal birth weight category twins had a higher prevalence of CP than singletons. When stratified by standard deviate, the prevalence of CP in twins was uniformly bigber that in singletons in all strata and the risk of CP for twins appeared to be rising as the birth weight increased. The results suggested that twinning was an independent risk factor of CP in all birthweight groups and the risk of CP started to rise as fetus matured.