Background: The aim of the study was to evaluate the association of body mass index (BMI), waist circumference (WC), and metabolic syndrome (MetS) with serum cystatin C (CysC) in a Chinese population.Methods: The population was composed of 5866 subjects. MetS was diagnosed using the American Heart Association/National Heart, Lung, and Blood Institute 2005 (NCEP-R) criteria. Covariates were analyzed using logistic regression and Spearman partial correlation.Results: In this population, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), high sensitivity C-reactive protein (hs-CRP), BMI, WC, systolic blood pressure (SBP), diastolic blood pressure (DBP), serum creatinine (Scr), and CysC were significantly higher, and HDL-C and the estimated glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration) (eGFR CKD-EPI ) were significantly lower in the MetS than in the non-MetS group. TG, LDL-C, FPG, hs-CRP, BMI, WC, SBP, DBP, and Scr were significantly higher, and HDL-C and eGFR CKD-EPI were significantly lower in the 4th quartile than in the 1st quartile of CysC. Logistic regression analysis showed that sex, age, hs-CRP, and CysC were independently associated with the presence of MetS (OR = 3.732, 1.028, 1.051, and 3.334, respectively; P < 0.05). No significant association between the presence of MetS and either Scr or eGFR CKD-EPI was observed. After adjustment for age and sex, BMI, WC, hs-CRP, and Scr were all positively correlated, whereas eGFR CKD-EPI was negatively correlated with CysC (r = 0.029, 0.061, 0.189, 0.227, and À0.210, respectively; P < 0.05).Conclusion: The present study revealed that the CysC was more closely associated with the presence of MetS, as compared Scr or eGFR CKD-EPI. CysC was positively correlated with BMI, and more strongly, positively correlated with WC and inflammation.Abbreviations: BMI = body mass index, CysC = cystatin C, DBP = diastolic blood pressure, eGFR CKD-EPI = estimated glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration), hs-CRP = high sensitivity C-reactive protein, LDL-C = lowdensity lipoprotein cholesterol, MetS = metabolic syndrome, SBP = systolic blood pressure, Scr = serum creatinine, TG = triglyceride, WC = waist circumference.