Previous studies identified correlations between suicide in prison and socio-demographic and crime characteristics. However links between these variables were not taken into account. In this paper we use a regression model to the study of the determinants of suicide in prison in order to isolate the individual effect of each variable. We confirmed previous observations such as the increase in suicides with the increase in length of imprisonment. The sex of the individual and the nature of the crime did not correlate with suicide rate. The major risk factors for suicide were high social status and a high degree of social and family integration. These results contrast with observations on suicide outside the prison environment, for which the contrary was found.