The aim of this study is to evaluate the association between body mass index (BMI) and cardio-metabolic risk factors and to determine the optimal BMI cut-off values in male and female subjects in Wuhan, China. We conducted a retrospective cross-sectional analysis of 20218 adult subjects (aged 18-85 years, 12717 men of them) who had health examinations at the health management center of Tongji Hospital of Wuhan in 2017. Multivariate logistic regression analysis was preformed to calculate the odds ratios (ORs) of cardio-metabolic risk factors. Receiver operating characteristic curve was used to determine the area under the receiver operating characteristic curve and optimal cut-off values for BMI predictive of cardio-metabolic risk factors. Of the 20218 participants, the percentage of males with overweight and obesity was as twice as that of females and the prevalence of hypertension, diabetes mellitus (DM), dyslipidemia, and hyperuricemia was significantly higher in males than females (27.18% vs 17.69%, 7.88% vs 4.16%, 41.97% vs 15.20%, and 34.50% vs 9.93%, respectively). Multivariate logistic regression analysis showed that higher BMI was a significant risk factor for hypertension (OR:1.27, 95% confidence intervals [CI]: 1.25-1.29), DM (OR:1.25, 95% CI:1.22-1.28), dyslipidemia (OR:1.26, 95% CI:1.25-1.28), and hyperuricemia (OR:1.25, 95% CI:1.23-1.27) after adjusting for age in both sexes. But in overweight or obesity status, females had higher ORs for hypertension and DM, and lower ORs for dyslipidemia than that in males. The optimal cut-off values of BMI for the presence of cardio-metabolic risk factors were among 24.25 to 25.35 kg/m(2) in males, which were higher than in females among 22.85 to 23.45 kg/m(2). The association between BMI and cardio-metabolic risk factors is different by gender. It is necessary to determine appropriate threshold for overweight status in men and women separately.