Objective To investigate the relationship between sleep duration and metabolic syndrome in obese children.Methods Sleep time was recorded and metabolic syndrome (MS) diagnostic criteria as blood pressure,body mass index (BMI) were measured among 311 obese children.The children were divided into 4 groups by sleep time while normal-weight children served as the control group.A disorderly multi-classification logistic regression method was used.Results Statistically,significant differences were found in the levels of BMI,blood pressure,fasting blood glucose and postprandial 2 h glucose and the incidence rates of abnormality on MS,blood pressure,fasting insulin,and BMI≥30 kg/m2 between the group with daily sleep time less than 8 h and the group with daily sleep time no less than 10 h (P＜0.05).Date from logistic regression analysis revealed that the reduction of sleep time was the risk factor of MS in obese children.Conclusion Insufficient sleep could greatly contribute to the occurrence of MS in obese children.