OBJECTIVE: To identify risk factors for poor child mental health in the southeastern Brazilian municipality of Taubaté. METHOD: In 2001 we carried out a representative school-based survey of Brazilian schoolchildren ages 7 to 14 years (response rate, 83%). We collected extensive data on child mental health and on potential risk and protective factors at baseline (N = 1,112) and collected follow-up information on mental health outcome after 3 years (N = 760). We used the Strengths and Difficulties Questionnaire as a dimensional measure of mental health at both time points and the Development and Well-Being Assessment to diagnose psychiatric disorder at baseline. RESULTS: Cross-sectionally, both dimensional and diagnostic measures of child psychopathology were associated with dangerous area, nontraditional family, parental stress, harsh physical punishment, poor general health, low IQ, repeating a year at school, and male gender. There were different cross-sectional associations with different types of psychopathology. Psychological difficulties were moderately persistent across time. Younger age, lower maternal education, and lower child's IQ predicted a worse prognosis even after adjusting for initial psychopathology. CONCLUSIONS: The multiple factors associated with Brazilian child mental health are broadly in line with previous findings elsewhere. Public health programs to foster child mental health need multiple targets, but may benefit a wide range of the population.