Objective: This study aims to identify the scientific evidence on the risks and effects of exposure to environmental contaminants in children during sensitive developmental periods. Data source: The search was performed in the Bireme database, using the terms: children's health, environmental exposure, health vulnerability, toxicity pathways and developmental disabilities in the LILACS, MEDLINE and SciELO systems. Data synthesis: Children differ from adults in their unique physiological and behavioral characteristics and the potential exposure to risks caused by several threats in the environment. Exposure to toxic agents is analyzed through toxicokinetic processes in the several systems and organs during the sensitive phases of child development. The caused effects are reflected in the increased prevalence of congenital malformations, diarrhea, asthma, cancer, endocrine and neurological disorders, among others, with negative impacts throughout adult life. Conclusion: To identify the causes and understand the mechanisms involved in the genesis of these diseases is a challenge for science, as there is still a lack of knowledge on children's susceptibility to many environmental contaminants. Prevention policies and more research on child environmental health, improving the recording and surveillance of environmental risks to children's health, should be an ongoing priority in the public health field. (C) 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda.