Imprisonment has long been regarded as a rightful reaction by society and a warning to perpetrators to stop committing crimes, but also as one of the most effective ways of figting against crime. The purpose of imprisonment is to resocialize the perpetrators of criminal offenses with the aim of changing their behavior and attitudes, in order to live in accordance with laws and social norms upon their release. Leaving jail, giving back to the community and adjusting is no easy task. For this reason, the institution in which the prisoner is serving a prison sentence plays an important role. Opportunities for re-socialization within the penitentiary institution will depend primarily on the social understanding of the purpose of punishment and imprisonment, the demographic, penological and criminological characteristics of the offender, the estimated degree of risk and need, the types and contents of the treatment, and factors that will directly affect the prisoner's motivation to participate in the offered re-socialization opportunities in the institution. The aim of this paper, reviewing domestic and foreing literature, is to explore contemporary re-socialization forms in the penological system and the importance of treatment programs for the purpose of re-socialization of offenders, i.e. enable them to live at large. Given that in today's postmodern and insecure world there is a constant increase in the prison population, and the topic is relatively rarely represented in domestic literature, it seems useful to address this topic in order to gain insights that could contribute to the development of resocialization in the prison system.