Objective: To evaluate the association between time spent on sedentary behaviors with anthropometric variables and the percentage of body fat. Subjects and Method: 43 schoolchildren (72% male) participated, aged between 6 and 9 years. Anthropometric measurements were weight, height, body mass index, arm circumference, waist circumference, subscapular skinfold, tricipital skinfold, arm muscle circumference, arm area, arm muscle area, arm fat area, and waist-to-height ratio. The percentage of body fat was measured using an isotopic technique considered the gold standard(deuterium). The average time spent on sedentary behaviors recorded by self-report, during three non-consecutive weekdays were school activity, extracurricular work at home, watching television, using electronic devices screens, and sedentary recreational activities. Results: 32% of the subjects were eutrophic considering the percentage of body fat. 52% of daily time is spent on sedentary activities with no significant differences between boys and girls, 12.4 h vs 13.37, respectively. Time spent watching television was significantly associated (p < 0,05) with greater values of the anthropometric variables [weight, body mass index, waist circumference, waist-to-height ratio, skinfold (subscapular and tricipital)], and body fat percentage. Conclusion: The time spent watching television is associated with an increase in body fat. There is an urge to promote recreational activities that involve an increase in moderate and intense physical activity in schoolchildren.