EN
This paper describes the theoretical aspects of internal security, i.e. its concept and the components comprising internal security such as public security, common security, and political security. The author briefly discusses the internal security system, including the role of prison officers. Moreover, the paper also describes the prison service system in Poland, the individual elements creating its structure, and the tasks of prison officers. There is also included a brief discussion of the reform of the prison service system in Poland, which started in 2017. Finally, the paper presents the up-to-date research findings from the Master’s thesis completed by the author in June 2016 entitled “Influence of Prison Service System on the Internal Security.