Despite its well-documented relation with visceral adiposity (VAT) and cardiometabolic risk (CMR), whether waist circumference (WC) should be measured in addition to body mass index (BMI) remains debated. This study tested the relevance of adding WC to BMI for the estimation of VAT and CMR. In the International Study of Prediction of Intra-abdominal Adiposity and Its Relationship with Cardiometabolic Risk/Intra-abdominal Adiposity, 297 physicians recruited 4,504 patients (29 countries). Both BMI and WC were measured, whereas VAT and liver fat were assessed by computed tomography. A composite CMR score was calculated. From the 4,109 patients included in the present analyses (20 ≤ BMI < 40 kg/m(2), 47% women), about 30% displayed discordant values for WC and BMI quintiles, despite a strong correlation between the 2 anthropometric variables (r = 0.87 and r = 0.84 for men and women, respectively, p <0.001). Within each single BMI unit, VAT and WC showed substantial variability between subjects (mean difference between 90th and 10th percentiles: 175 cm(2)/16 cm and 137 cm(2)/18 cm for VAT/WC in men and women, respectively). Within each BMI category, increasing gender-specific WC tertiles were associated with significantly higher VAT, liver fat, and with a more adverse CMR profile. In conclusion, this large international cardiometabolic study highlights the frequent discordance between BMI and WC, driven by the substantial variability in VAT for a given BMI. Within each BMI category, WC was cross-sectionally associated with VAT, liver fat, and CMR factors. Thus, WC allows a further refinement of the CMR related to any given BMI.