As part of its mandate to conduct epidemiological surveillance of occupational risks, the Department of Occupational Health (DST) at the French Institute for Public Health Surveillance has launched a workplace surveillance program aimed at establishing epidemiological monitoring of workers in sectors of interest. The objective is to detect any excess incidence of certain diseases in these sectors, or to identify disparities across occupations, sectors, or occupational exposures. This can help identify work-related health issues, assess their impact on workers, and guide or evaluate prevention efforts. With this in mind, the analysis of causes of death constitutes the first component, allowing for an initial assessment of mortality in the population according to occupational characteristics. The 20-year analysis of the population of current and former EDF-GDF workers is the first study of its kind conducted at the DST. It is presented here to illustrate what such a study entails and what the main results that can be derived from it are. (R.A.)