Abstract： Objective To explore the correlation between serum levels of Cystatin C and metabolic syndrome.Methods This study was randomly conducted in 506 persons,including 191 patients with metabolic syndrome (MS),210 with metabolic disorder (MD) and 105 persons in normal control (NC) group.According to serum levels of Cys C,the clinical data were also divided into 3 groups of lower tertile (T1,n =165),middle tertile (T2,n =172) and upper tertile (T3,n =169).Body mass index (BMI),waist circumference (WC),waist-hip ratio (WHR),fasting plasma glucose (FPG),low-density lipoprotein cholesterol (LDL-C),triglyceride (TG),high density lipoprotein (HDL),creatinine (Cr),estimated glomerular filtration rate (eGFR),microalbuminuria (MAU),systolic blood pressure (SBP),diastolic blood pressure (DBP) and pulse pressure (PP) were measured and their mutual relations evaluated.Results Statistically significant differences (all P ＜ 0.01) existed among T1,T2 and T3 groups in the mean values of BMI,waist circumference,WHR,FPG,LDL-C,TG,Cr,eGFR,MAU,SBP,DBP and PP.As tertile levels of Cys C increased,MS morbidity rates became all remarkably augmented (P ＜ 0.01).The MS component scores had significant statistical differences among the patients of T1,T2 and T3 groups (P ＜ 0.01).As the MS component scores increased,the level of Cys C rose in these patients.The higher MS marks were,the higher serum concentration of Cys C was in these patients.The plasma concentration of Cys C in MS patients was closely related with WC,LDL-C,FBG and blood pressure (all P ＜ 0.05),not related with TG levels and negatively correlated with HDL-C levels (r =-0.352,P =0.01).WC,Cys C,LDL-C,MAU and PP were significantly associated with MS.And the value of OR between Cys C and MS was 2.943 (95％ CI 1.276-3.914).Conclusion Cys C is significantly associated with MS.As MS scores rise,the level of Cys C increases.