Introduction - In France, the suicide rate in prisons was significantly higher than in the general population in 2011. We reviewed the evolution of the crude suicide rate in prisons since 1945 and sought to understand the trends observed. Materials and Methods - The suicide rate in prisons in metropolitan France has been compared since 1945 to that observed in the general male population (ages 15 to 59). Data covering three and a half years of incarceration from the national inmate database of the Directorate of Prison Administration (DAP) confirmed certain risk factors identified in the literature. Annual data from the DAP were used to describe changes in the incarcerated population that may have played a role in suicide trends. Results—From 1945 to 2010, the suicide rate in prisons rose significantly, from 4 to 19 per 10,000 people, and differed from the rate observed in the general population. Starting in 1955, the proportion of women became marginal, and the size of the incarcerated population increased. After initially rising, the proportion of pretrial detainees declined. More recently, the use of short-term sentences has become more widespread. The proportion of individuals convicted of sexual assault has increased, as has, more recently, the proportion of those convicted of intentional violence. Discussion and Conclusion - Prison conditions and the social and health profiles of inmates could not be studied over time, but changes in the criminal profile of inmates likely played an important role in the rise in suicide rates. (R.A.)