Analyses of data from the representative 2002 National Nutrition and Health Survey were used to assess the likelihood of metabolic complications of overweight and obesity in Chinese children aged 7–17 years. Chinese criteria for body mass index classification were used for overweight and obesity with the 75th percentile US adolescent values for waist circumferences and all the metabolic criteria for blood pressure, lipids, fasting glucose established for US adolescents. Diabetes in 7–12-year-olds was 0.2% and 0.4% in children aged 12–18 years. Prevalences of dyslipidaemia (61.9%), hypertriglyceridaemia (18.2%) and low high-density lipoprotein cholesterol (56.1%) were high and 16.0% of 15–18 years had hypertension. The overall prevalence of the metabolic syndrome was 3.3% with more than half the children having at least one metabolic abnormality and 19.8% having at least two. All the metabolic parameters were significantly elevated in the overweight and obese children except high-density lipoprotein cholesterol. These data emphasize the marked sensitivity of Chinese children to the metabolic complications of overweight and obesity and amplify the need for early preventive measures.