Resumo. ABSTRACT The aim of this study was to evaluate the influence of body mass index (BMI) on the postural balance of schoolchildren. This was a case-control study involving 128 students aged 6 to 9 years, divided into a case group (overweight) and a control group (eutrophic) of 64 subjects each. Static and dynamic balance was assessed using Fonseca’s Psychomotor Battery. BMI was used as an indicator of nutritional status. Simple and relative frequencies, absolute numbers and the chi-square test were used for statistically analysis, with a level of significance of 5%. Most students performed better in dynamic than in static balance. Significant differences were only found for the subtask of standing on tiptoes in the static balance assessment (p<.05), with no significant differences in the other variables.