Background: Correctional staff has been shown to be an occupational group at greater risk of suicide.Correctional officers are also more likely to suffer from burnout because of their difficult working conditions.However, the reasons for the greater risk of suicide have never been investigated.Our objectives were to estimate suicide mortality of French correctional staff and to compare it to the general population and other occupational groups; and to identify the determinants of suicide.Methods: All available data of the Prison Administration of the French Ministry of Justice were used to estimate suicide mortality among correctional staff.Mortality rates were compared to those of the general population (data of the French centre of medical causes) and to those of prison staff (data of the prison administration of the Ministry of Justice) using standardisation methods.In a second step, all correctional officer suicides of the years 2008, 2009 and 2010 (n=32) were investigated by interviewing key informants.For each case three informants were selected: a member of the family or a close friend, a colleague and a supervisor.Data were collected using standardized questionnaires exploring socio-demographics characteristics, life events, social integration and support, health services use, mental health, occupational stress, impulsivity and aggressiveness.All these information were summarized in a timetable representing each case life trajectory.Each case was then appraised by at least two experts to conclude on the determinants of the suicide.Results: Between 1991 and 2010, among the 20,000 correctional officers, the suicide rate was equal to 34.4 p 100,000.After adjustment for gender and age, this was statistically larger than suicide mortality in the French general population (+31%).22 cases were investigated (response rate: 76 %).All deceased correctional officers were suffering from psychological distress (most of them from depression).After mental health, the main cause of suicide was problems in the married life (81% of the cases) and occupational stress (62 % of the cases).Finally, three distinct types of life trajectories could be identified by a qualitative analysis.Discussions: This study showed that there was not one single profile of life trajectory: screening and support of distressed correctional officers have to be prioritized.Moreover they show that a reflection has to be made on working conditions of correctional staff, in particular in order to improve image and self-esteem in this occupational group.This study helped the prison administration to elaborate and improve strategies to prevent suicide among correctional officers.