For the majority of prison staff, working in a prison constitutes a unique work environment, as they are exposed to a variety of specific occupational hazards inherent to their duties (stress, feelings of insecurity, etc.). In this cohort study, the French Institute for Public Health Surveillance analyzed the causes of death among individuals who were employed by the PA between 1990 and 2008. All-cause and cause-specific mortality among more than 40,000 current and former staff members was compared to that of the general French population over the same period using standardized mortality ratios (SMR). The 1,754 deaths observed represent an all-cause undermortality typically seen in worker cohorts. A statistically significant excess of suicide is observed among men (+21%). This observation was made between 1990 and 2008, with no recent increase or decrease. The excess specifically concerns the occupations of prison guard and technical assistant. No positive association was observed between the occupational indicators studied (type of facility, prison occupancy rate) and the risk of suicide. This excess of suicide is consistent with the literature and the nature of prison guard work. The available data do not allow for an assessment of whether the observed excess is primarily linked to occupational or personal factors. In any case, the results underscore the importance of continuing suicide prevention measures in the prison system, pursuing the implementation of a health surveillance system, and promoting the conduct of etiological studies. This study highlights the value for an institution of having an epidemiological surveillance system for the health status of all its staff, which provides quantified and objective data, particularly to guide and monitor the implementation of prevention measures.