The main aim of this cross-sectional study was to determine whether the increased body mass index (BMI) characterizing short-duration sleeping children is related to an increased predisposition to abdominal adiposity. A total of 422 children (211 boys and 211 girls) involved in the "Québec en Forme" Project were tested for body weight, height, waist circumference, and sleep duration. As there was no gender interaction with the other factors, a partial regression of waist circumference on hours of sleep was performed for both genders combined, adjusting for age, sex, BMI, parental obesity, parental education, total annual family income, frequency of taking breakfast, watching television, playing videogames, computer use, and frequency of practicing sports activities outside of school. Sleep duration had an independent effect on waist circumference, with the correlation between these variables remaining significant after adjustment for BMI and the several other covariates (r=- 0.17, p<0.001). In conclusion, these results suggest that short sleep duration favors abdominal adiposity in children. This finding is of particular concern since abdominal obesity is an important feature of the metabolic syndrome.