Prison is a social entity in which there are citizens who are currently serving a criminal period. Even though prisoners are in the process of training in the prison and are in a limited environment, as social creatures they do not lose their ability to be able to exercise of power. As social creatures, they certainly interact with each other within the scope of activities in prison. This research tries to explore the process of forming the structures formed in Klaten prisons and how their structures are also different from the informal association networks outside the prison. The objects in this study were the assisted residents in the Klaten Class IIB Penitentiary. Data collection techniques used in this study include direct observation, interviews, and literature study. The results showed that the social structure formed in prisons, prison officers clearly occupy the highest position and position because they are representatives of the state that has legitimacy and all legal instruments of power to foster prisoners in prisons. The formation of social structures for prisoners can be said to be unique, this is because there are several factors which then influence their position and position in prison. These factors are; First, the prisoners' ability to build closeness to prison officers. Second, the economic capacity of the prisoners, the third is the expertise possessed by prisoners, and the fourth is the factor of the crimes committed by the prisoners.