To present an up-to-date review about environmental influences on child mental health, describing major risk factors and discussing recommendations for intervention by pediatricians.MEDLINE, PsycLIT and Lilacs, technical books and publications about child development and child and adolescent mental health problems and health promotion.Children are exposed to multiple risk factors, among them high prevalence of disease, premature birth, being born from a problematic pregnancy, and living in poverty. This negative chain of events increases the risk for emotional problems. The negative effects on development and behavior result from the complex interaction between genetic, biological, psychological and environmental risk factors. The main factors influencing the mental health of children are the social and psychological environment. The cumulative risk effect is more important in determining emotional problems in children than the presence of one single stressor, regardless of its magnitude.Environmental factors play an important role in the etiology of emotional problems in childhood. An adequate clinical investigation allows pediatricians to identify risk factors for the development of mental health problems and to ensure early intervention for children at risk.