This publication was prepared by the WHO European Centre for Environment and Health, Rome Operational Division, with support from the European Environment Agency, building on a collection of background papers prepared for the Third Ministerial Conference on Environment and Health in London in 1999. It provides anover view of the available evidence of the relationship between the physical environment and children’s health, identifying both research needs and policy priorities to protect children’s health from environmental hazards. The report aims to assist policy-makers and public health officials as they develop plans and strategies to address the most serious environmental health threats to children. It is also intended to promote a better understanding of children’s environmental health issues within the scientific and professional communities involved in both child health and environmental protection.