In Quebec, a law requires physicians and laboratory directors to report to local public health authorities any diagnosis or clinical signs suggestive of a disease of chemical or physical origin. There are currently 10 reportable diseases (MADO) of chemical or physical origin. Surveillance and monitoring of these diseases are essential to ensure the protection of public health and to plan preventive interventions. In 2005, the Institut national de santé publique du Québec developed a reporting system for chemically-induced Mado that meets the security criteria of Quebec’s health and social services network. This web-based system allows for the entry and recording of MADO reports and includes several data validation checks, such as cross-validation between variables, duplicate detection, and more. The surveillance products section presents regional and provincial MADO report statistics in the form of graphs, tables, and maps. A location tool displays exposure sites on a map, enabling stakeholders to better manage data, among other things, by facilitating the detection of outbreaks. There has not yet been a formal evaluation of the Mado-Chimique system, as it was only recently implemented in the network. (R.A.)