OBJECTIVE This study was designed to evaluate the epidemiology and clinical characteristics on metabolic syndrome (MetS) among overweight and obese children aged from 6 to 13 years old in Kazakh ethnic populations. METHODS Based on the data including body mass index (BMI), waist circumference (WC) and blood pressure measured from the 'Kazakh ethnic child Health examination study in Yili', 5360 Kazakh children aged 6 - 13 were screened for overweight and obesity in Xinjiang, using the Chinese BMI cutoffs for schoolchildren (7 - 18 years) and WHO growth reference for school-aged children and adolescents (6 year). Simultaneously a group of children with normal BMI were selected as the control group. Fasting plasma glucose (FPG), insulin (FINS), serum high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were examined. HOMA-IR index was calculated to estimate the individual insulin resistance. Children under study were older than or equal to 10 years and met the criteria according to the definition of metabolic syndrome, prophylaxis and treatment on Chinese children and adolescents, proposed by the Society of Pediatrics in China or NCEP-ATPIII definition as MetS. Risk factors related to cardiovascular diseases were analyzed according to the criteria by the Society of Pediatrics among those aged from 6 to 10 years old children. Connection between waist-to-height ratio (WHtR) and biochemical indexes was explored. RESULTS Prevalence rates of MetS according to the criteria from Society of Pediatrics in China were: 0%, 9.57%, 19.64% in the normal weight, overweight and obese children, respectively. The rates diagnosed by NCEP-ATPIII definition were 0.64%, 2.61%, 16.07% respectively. The detective rates of individual MetS component among obese children were: 78.95% for abdominal obesity, 29.82% for elevated BPs, 26.32% for high TG, 22.81% for low HDL-C, 0.88% for FPG. High TG (31.15%), abdominal obesity (23.77%) and low HDL-C (22.95%) appeared as the leading three abnormal indices among the overweight children. With increased BMI, the clustering of MetS components were also remarkably increasing. The detective rates of cardiovascular-related risk factors among overweight or obesity children from 6 to 10 years old were:abdominal obesity or obesity, low HDL-C, high TG, impaired FPG, elevated BPs. Differences were seen between overweight or obesity children and normal weight children on the detective rates of high TG, low HDL-C, abdominal obesity or obesity. WHtR was related with FINS, HOMA-IR index and LDL-C. CONCLUSIONS MetS seemed epidemic among obese Hazakh children. Abdominal obesity, elevated BPs and high TG were the leading three abnormal factors among obese children. Compare to NCEP-ATPIII, abnormal biochemical indices on overweight Kazakh children seemed to be more sensitive, proposed by the Society of Pediatrics in China.