The aim of this thesis is to analyze violence in the Croatian prison system with an emphasis on differences in the sex of prisoners. The research was conducted on a sample of prisoners from Zagreb Prison, Požega Prison, Lepoglava Penitentiary, Turopolje Penitentiary, Glina Penitentiary, Požega Penitentiary, Lipovica Penitentiary and the Juvenile Department of the Požega Penitentiary. The study included a total of 387 prisoners, of whom 318 (82.2%) were men and 69 (17.8%) were women. The results showed that in physical violence, a difference was found in only one (pushing another prisoner) out of thirteen variables in relation to gender, in a way that men were more violent than women. In the part of verbal violence, statistically significant differences were found in two variables (swearing at another prisoner and invoking derogatory names) in a way that men were more violent than women, while statistically significant differences were not found between male and female prisoners. Given the level of security of the ward, in the subsample of male prisoners, physical and verbal violence is significantly more common in closed conditions of imprisonment, while in women prisoners threats are more prevalent in closed conditions of imprisonment. No statistically significant differences were found in the different forms of violent behavior given the part of serving the sentence. In relation to the differences in violent behavior in the penitentiary with regard to the violence of the committed criminal offense due to which they are serving a prison sentence, in the subsample of male prisoners physically and verbally violent are prisoners who committed a violent crime, while in the subsample of female prisoners no differences were found.