This paper analyses and determines the penology characteristics and the social-protective needs of the special categories of perpetrators of criminal offences placed in institutional treatment: the specific population of minors and young adults in juvenile detention centres, the female population in institutional treatment facilities, and the population of convicted seniors. This work observed and critically analysed questions regarding their pension insurance, family and health care, education/training and labour integration, and job training. It also covers the characteristics of the organization and the life and work conditions in Croatian correction facilities. This paper thoroughly covers the legal status of convicted persons in institutional treatment; analysing both domestic and international legislation. With regards to the ultimate goal of the rehabilitation process in terms of the social inclusion of the population which is analysed in this work highlights the importance of social policies in post-treatment. In doing so, it notes the necessity of merging and publishing the awareness and legitimacy of the relationship between social policy and the crime prevention policy. The paper also looks at noticeable new trends and problems in accordance with them, and predicts the measures needing to be taken by the developed Croatian social politics in order to be resolved.