Abstract: Objective To estimate the prevalence of metabolic syndrome(MS)and its components among the urban population in Xilinhaote,Inner Mongolia.Methods Epidemiology investigation was carried out among 1060 residents who took their health examination in Xilinhaote hospital during September 2006 to March 2007.MS and its components was diagnosed according to the definition proposed by IDF in 2005.Results The crude prevalence of MS in the subjects was 29.2%,and age-adjusted prevalence was 25.0%,with higher rate in men than in women(P<0.05).The aged-adjusted prevalence of central obesity,high blood pressure,high blood glucose,hypertriglyceridaemia and low HDL cholesterol was 39.5%,53.1%,23.8%,38.8% and 0.2% respectively,with higher rates in men than in women except low HDL cholesterol(P<0.5).The prevalences of MS,central obesity,high blood glucose and hypertriglyceridaemia were in a high level in the subjects of 30 to 50 years old,and showed a mild decrease after 60.The prevalence of MS and its components in women increased with age,especially after 50 years old.The prevalence of MS in Mongolian nationality was higher than in Han nationality.About 77.7% of the subjects had ≥1 metabolic disorder factors,and only 22.3% were completely normal.The most common combination of MS was central obesity,high blood pressure and hypertriglyceridaemia.Conclusion The prevalence of MS and its components are high in Xilinhaote population.We should take appropriate measures to control the prevalence of MS.