This cross-sectional study aimed to: (i) investigate whether obesity and overweight defined according to body mass index (BMI) are good predictors of body fat excess, abdominal adiposity and hypertension in 769 Brazilian children aged 6-11 years, (ii) assess the relationship between overweight/obesity and cardiovascular risk factors. Overweight and obesity were estimated using cut-off points corresponding to World Health Organization 1 and 2 SD (standard deviation) scores. Based on the results of a multiple logistic regression analysis, overweight and obesity were significantly associated with body fat excess, abdominal adiposity and hypertension. The prevalence of obesity (10.7%), overweight (18.7%), abdominal adiposity (17.6%) and systolic (10.1%) and diastolic hypertension (9.3%) was high in this population of Brazilian children. The cardiovascular risk factors increased significantly according to the BMI SD scores, indicating that in epidemiologic studies, BMI may be a good indicator of risk for cardiovascular diseases.