OBJECTIVE: To study the sleep time and the prevalence of sleep disorders in children at ages of 2-12 years in Changsha City. METHODS: A total of 3 756 children at ages of 2-12 years were randomly sampled from five districts of Changsha City from June 2006 to April 2007. A questionnaire survey was performed on their parents.RESULTS: The average daily sleep time in the subjects was 10.60 hrs. The average daily sleep time among different age groups (1 year as a group separation) was different. It was 12.26, 11.57, 11.33, 11.26, 10.95, 10.64, 10.62, 10.45, 10.28, 9.83 and 9.61 hrs respectively in the 11 age groups of 2 to 12 years of age. The prevalence of sleep disorders in children at ages of 2-12 years was 40.9%, including frequent sleep snoring (8.2%), choke/gargling (1.5%), sleep apnea (0.8 %), sleep inquietude (7.6%), mouth breathing (4.9%), hyperhidrosis (22.6%), limbs spasm (3.2 %), sleep teeth grinding (9.5 %), sleep talking (5.5 %), sleep walking (0.9 %), nocturnal enuresis (2.5%), waking up by choke (1.9%), remaining wakefulness in the night due to too much daytime sleep time (1.5%), going to sleep too early (2.1%), night awakenings (1.6%), and screeching or crying during sleep (1.8%). The prevalence of different sleep disorders was different in children between boys and girls and among different age groups. CONCLUSIONS: The average sleep time in children at ages of 2-5 years is less than the reference value recommended by the domestic child health care textbook. There is a higher prevalence rate of sleep disorders in children at ages of 2-12 years in Changsha City than the reported data in other cities.