Background and aimsFew data exist regarding the gender differences in the relationship between triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio and cardiometabolic risk leading to atherosclerotic cardiovascular disease (ASCVD). We investigated, by gender, the association between the TG/HDL-C ratio and metabolic syndrome (MetS) and its components in the Japanese, who are less obese than their Western counterparts. Methods and resultsA population consisting of 10,373 participants (average age, 47.6 ± 12.6 years, 60.9 % men) at the Health Planning Center of Nihon University Hospital between April 2019 and March 2020 was studied using a cross-sectional study method. The TG/HDL-C ratio and proportion of visceral obesity increased approximately parallelly with age in women; however, these parameters did not change proportionally with age in men. Accordingly, receiver operating characteristic analysis revealed the accuracy of the TG/HDL-C ratio as a predictor of visceral obesity based on the Japanese MetS criteria (women vs. men: area under the curve, 0.797 vs. 0.712, p < 0.0001; sensitivity, 82.4 % vs. 59.9 %; specificity, 61.1 % vs. 71.1 %; cutoff value, 1.075 vs. 1.933, respectively). Furthermore, a higher TG/HDL-C ratio in women reflected the status of MetS and its components compared with men in multi-logistic regression analysis. ConclusionAn increased TG/HDL-C ratio in women may be involved in MetS and its components compared to men. We may pay attention to visceral obesity and increased TG/HDL-C ratio to prevent ASCVD risk in women, even in the Japanese population, which generally contains a lower proportion of obesity than in Western populations.