Abstract: To investigate the relationship between free fatty acid(FFA) and insulin resistance(IR) in Kazakh people with metabolic syndrome(MS) in Xinjiang Uygur Autonomous Region.Methods Totally 195 MS patients and 120 health controls were sampled.FFA was measured with colorimetry and fasting insulin(FINS) was measured with radio immunity method,and the insulin resistance index determined by hemeostasis model assessment (HOMA_IR) was calculated.Results FFA and HOMA_IR were significantly higher in the MS than those in the controls(FFA:0.57±0.22 vs 0.46±0.22,P=0.000 for male,0.65±0.24 vs 0.52±0.17,P=0.000 for female; HOMAIR:5.17±4.89 vs 1.62±1.29,P=0.000 for male,3.75±3.37 vs 2.20±1.53,P=0.004 for female).FFA and HOMA_IR were correlated with MS and the prevalence of MS increased with FFA level and HOMA_IR.After adjustment for age,gender,smoking,alcohol consumption,body mass index(BMI) and HOMA_IR using a multivariale logistic regression,FFA was significantly associated with MS.The odds ratio(OR) of MS for the people in the third and fourth quartile of FFA was 4.374 and 4.208 (all P< 0.005).HOMA_IR was significantly associated with MS and the odds ratio (OR) for the fourth quartiles of HOMA_IR was 8.552.FFA and HOMA_IR correlated significantly with triglyceride (TG),high density lipoprotein cholesterol(HDL-C),fasting plasma glucose(FPG),systolic blood pressure(SBP),diastolic blood pressure(DBP),and waist circumference(WC) in the simple correlation analysis(P< 0.05).After adjustment for age,gender,and HOMA_IR in partial correlation analysis,FFA was correlated significantly with WC and DBP only.Conclusion IR may be an important and independent risk factor for MS and FFA may not be an independent risk factor but it may lead to MS and the components of MS through inducing IR by other mechanisms.