To identify the prevalence of internalizing and externalizing behavior problems among preschoolers from the city of Salvador, state of Bahia, Brazil, and their associations with maternal mental health and family characteristics. Methods: This was a cross-sectional study of 349 children aged 49 to 72 months, randomly selected from 20,000 households representing the range of socioeconomic and environmental conditions in Salvador. In 1999, we assessed sociodemographic variables and family environment characteristics. In 2001, we used the Child Behavior Checklist to measure and describe the frequencies of behavior problems. We conducted bivariate and multivariate analysis to estimate associations between family and maternal factors and prevalence of behavior problems. Results: The overall prevalence of behavior problems was 23.5%. The prevalence of internalizing problems was 9.7%, and that of externalizing problems, 25.2%. Behavior problems were associated with several maternal mental health variables, namely: presence of at least one psychiatric diagnosis (odds radio [OR] 3.01, 95%CI 1.75-5.18), anxiety disorder (OR 2.06, 95%CI 1.20-3.46), affective disorder (OR 2.10, 95%CI 1.21-3.65), and mental health disorders due to use of psychoactive substances (OR 2.31, 95%CI 1.18-4.55). Conclusion: The observed prevalence of child behavior problems fell within the range reported in previous studies. Maternal mental health is an important risk factor for behavior problems in preschoolaged children.