OBJECTIVE To examine risk factors regarding short sleep duration among Chinese school-aged children. METHODS A random sample of 20,778 children aged around 5-11years participated in a cross-sectional survey, which was conducted in eight cities of China in 2005. A parent-administered questionnaire was used to collect information on children's sleep duration and possible related factors from eight domains. Short sleep duration was defined as total sleep duration <9h per day. RESULTS In all, 28.3% of the sampled children slept <9h per day. The multivariate logistic regression identified, after adjusting for demographic and socioeconomic variables, factors associated with short sleep duration: more television viewing during weekdays (OR=1.21, p=0.004), more frequent computer/internet using (OR=1.17, p=0.006), earlier school starting time (OR=1.10, p=0.020), more time on homework during weekdays (OR=1.66, p<0.001) and weekends (OR=1.14, p=0.001), poor bedtime hygiene (e.g., having drinks with caffeine after 6:00PM [OR=1.22, p<0.001], doing exciting activities during bedtime [OR=1.16, p<0.001], and irregular bedtime [OR=1.55, p<0.001]), and shorter sleep duration of parents (mother: OR=1.31, p<0.001 for sleep duration <6h and OR=1.24, p=0.006 for 6-8h; father: OR=1.52, p<0.001 for <6h and OR=1.19, p<0.001 for 6-8h). CONCLUSIONS Factors associated with sleep duration covered multidimensional domains among school-aged children. Compared to sleep environments and chronic health problems, school schedules, lifestyle patterns, and parents' sleep habits had greater impact on children's sleep duration, indicating the existing chronic sleep loss in school children could be, at least partly, intervened by reducing the use of visual technologies, by changing the school schedules, by improving the sleep hygiene routine, and by regulating parents' sleep habits.