The topic of this thesis are the inmates' rights and the ways of protecting these rights in the Republic of Croatia. The central figure of penitentiary law is the inmate who is deprived of liberty, but he/she has kept the other rights that are guaranteed by the Constitution of the Republic of Croatia, international agreements and laws. Inmates' rights, their protection and review of the system of execution of prison sentences in the Republic of Croatia are provided for by the Law on execution of prison sentences. In the Republic of Croatia, remedies for the protection of inmates' rights in the prison system are complaint and appeal. Every day the inmates can submit complaints to the prison staff, the executing judge and the Central office, and the complaints addressed to the above mentioned persons and authorities can be in oral and written form and must not be censured. Review of the execution of prison sentence is achieved both at national and international level. At national level there is judicial and non-judicial review. Direct judicial review is performed by the executing judge under powers to review the legality in the procedure of execution of prison sentences and to ensure equality of the inmates before the law. Indirect judicial review of the execution of prison sentence and maintaining constitutional rights that are guaranteed to inmates is performed by the Constitutional Court of the Republic of Croatia. Non-judicial review of the execution of prison sentence at national level can be administrative control in the broad sense, which is performed by the ombudsman. Administrative control in the broad sense consists of administrative control in the strict sense and of inspection. At the international level, the non-judicial review is performed by the authorities such as the European Committee for the Prevention of Torture, and the judicial review by the European Court of Human Rights. It can be concluded from the thesis that the inmates, just as all other people, have their guaranteed rights, but they rights are often violated in practice.