Abstract: Objective To explore the status of metabolic syndrome(MS)in Mongolian people of agricultural and pastoral areas in Tongliao city of Inner Mongolia with different diag nostic criteria proposed by the IDF in 2005,ATPⅢin 2005 and CDS in 2004.Methods A survey on cardiovascular risk factors was conducted in August 2003-August 2004.Atotal of 2536 Mongolian people aged 20 orelder completed the biochemical examination.MS prevalence was calculated according to three definitions.The results of MS components distribution and risk factor agg regation were analyzed and prevalences derived from the three deftnitions were compared.Results The age-adjusted prevalence of MS in Mongolian people was 17.1% for IDF criterion,22.9% for ATPⅢcriterion and 8.1% forCDS criterion,respectively.The agreement in the diagnosis of MS using IDF and ATPⅢ,IDF and CDS,ATPⅢand CDS was 93.5%,85.0% and 81.6%,respectively.Among the subjects who had three or more MS components,there were 100% subjects detected by ATPⅢcriteria,76.1% by IDF criteria and 33.5% by CDS criteria respectively.Conclusion This investigation show svery high agreement in the diagnosis of MS using IDF and ATPⅢ,and moderate agreement when using CDS and other two criteria in Mongolian people.The cutoffvalue of waist circumference(WC)in IDF and ATPⅢseems high for Chinese men.