BACKGROUND AND AIMS: To assess the associations between serum concentrations of branched-chain amino acids (BCAAs)-valine, leucine, and isoleucine-and different anthropometric markers, including leptin and adiponectin levels, as well as body composition. METHODS AND RESULTS: This cross-sectional study used data from the CoLaus|PsyCoLaus and the OsteoLaus studies in Lausanne, Switzerland. Anthropometric markers included the conicity index (CI), body roundness index (BRI), a body shape index (ABSI), body mass index (BMI), and waist circumference, among others. Grip strength was used as a proxy for muscle mass. Bivariate analysis revealed that most anthropometric markers were positively correlated with BCAA, while adiponectin levels was negatively correlated with BCAA. These correlations were generally stronger in males than in females, with the exceptions of CI, ABSI, and adiponectin. After multivariable analysis, weight and BMI showed the strongest association coefficients with BCAA in males, while in females the strongest associations were found for waist circumference and waist-to-height ratio. No significant associations were found between the ABSI and BCAA levels in males, or between grip strength and BCAA levels in females. Stepwise linear regression identified BMI in males, and waist circumference in females as the anthropometric markers most strongly positively associated with BCAA. CONCLUSION: We observed a significant difference in the association between BCAA levels and anthropometric markers by sex. BMI displayed the strongest positive association with BCAA levels in males while in females, waist circumference exhibited the strongest association.