Objective: To assess the prevalence of ADHD, mental health status, and risk factors in a sample of Brazilian children. Method: Target sample consisted of all children from 5 to 13 years registered in the public elementary school. Children with ADHD were compared with those without ADHD for sociodemographic, risk factors, and Child Behavior Checklist (CBCL) symptom dimensions. Multivariate models estimated determinants of ADHD diagnosis. Results: Of the target sample, consents and complete information were obtained from 1,830 children (91.8%). The prevalence rate of ADHD was 5.1% (95% confidence interval [CI] = [4.2, 6.2]). In contrast to controls, children with ADHD presented higher levels of symptoms in the CBCL dimensions. In multivariate analyses, the diagnosis of ADHD was significantly influenced by maternal educational status (p = .019), income class (p = .012), and prenatal exposure to tobacco (p = .032). Conclusion: Prevalence and demographic features of ADHD in Brazil are similar to what has been reported worldwide. (J. of Att. Dis. 2012; XX(X) 1-XX)