Abstract Introduction . Traditionally, the body mass index (BMI) is used to describe anthropometric measurements and to assess weight-related health risks. However, the abdominal circumference (AC) might also be a valuable parameter to estimate this risk. This study aims to describe an association between the BMI and the AC. Material and Methods . Participants were recruited during the Brussels Food Fair in 2014. They completed a questionnaire with their medical history, and health related parameters such as blood pressure, weight, height and AC were measured. Results . In total, 705 participants were analyzed. Men had a mean BMI of 27.3 kg/m 2 and a mean AC of 98.7 cm. Women had a mean BMI of 26.0 kg/m 2 and a mean AC of 88.2 cm. The Pearson’s correlation coefficient between the BMI and the AC was 0.91 for men and 0.88 for women. There was a strong positive correlation between the BMI and the AC. In the identification of patients at high risk for weight-related diseases, the use of the AC identified more patients than the BMI. Especially more women were ranking in a higher risk class with the AC than with the BMI classification. Both the BMI as well as the AC identified most diseases with an increased relative risk. Conclusion . There is a strong correlation between the BMI and the AC. There are too few arguments to prefer the use of AC above the BMI to detect people at high risk for weight-related diseases.