Environmental health surveillance (EHS) can be understood as "public health surveillance of health related to the environment." This allows us to define it by extension from the definition of public health, incorporating all of the latter’s attributes: the collection of health data, for example, but also that of environmental data. This implies that the term “environment” must be defined, along with its components (environment, vector, agent). The surveillance process involves several stages: from design (selection of relevant indicators and necessary data) to the dissemination of results, including data collection, analysis, and interpretation. Today, in France, environmental health surveillance focuses on health risks linked to environments or agents, on diseases potentially linked to the environment, and on populations considered sensitive to certain environmental conditions. It utilizes existing surveillance systems, reports, and databases, but may also incorporate longitudinal or cross-sectional studies or surveys. Environmental health surveillance must also, like general surveillance, incorporate intervention indicators and examine the relationships between these and other indicators (health, environmental, and population-based). It must also utilize economic tools (cost-effectiveness, DALYs, etc.) as part of a decision-support approach. Finally, environmental health could benefit from the implementation of integrated surveillance systems. (R.A.)