Chemical contamination refers to the presence of chemicals in places where they should not be found, including the workplace, home, food and environment. It can also refer to chemicalsthat are present at higher concentrations than usual or at concentrations that are considered to be hazardous to human health.The aim of the present study is to review recent research related to the effects of the main inorganic and organic chemical contaminants on brain development and mental health of preschool and school-age children.In addition, possible ways of preventing and reducing chemical contamination in schools are suggested. The results of recent findings showed that the exposure of children to chemical contaminants was associated with structural changes in the developing human brain in regions that affect working memory, attention and executive function. Intelligent quotient deficits,motor and learning problems,autism spectrum and attention deficit hyperactivity disorders were observed in children exposed to various chemical contaminants. Furthermore, other studies showed that toxic environmental exposure was related to the appearance of antisocial and violent behaviour as well as other psychological issues.Therefore, it can be concluded that chemical contaminants may affect the cognitive function and the mental health of preschool and school-age children.