Objectives:
The main research objective of the presented study was to show the effectiveness of corrective and educational interventions carried out in prisons for persons convicted of aggressive crimes.

Methods:
Experimental study. Two research groups were randomly identified (experimental and control). Participants qualified for the experimental group participated in a correctional program for perpetrators of violent crimes. Study participants assigned to the control group did not participate in a similar program. In total, 142 people joined the Aggression Replacement Training (ART) in the experimental group and 156 in the control group. Before the start of the program and after its completion, the study participants completed a set of psychological questionnaires used to measure aggression, and information from penitentiary records was also analysed. Five years after leaving prison, further analyses of reoffending were conducted.

Results:
Aggression Replacement Training seems to be an important and effective way of influencing perpetrators of aggressive crimes. In the study on the prison population, it obtained positive results in the short term perspective, i.e. in relation to the time during which the program was implemented and immediately after its completion.

Conclusions:
1. Convicts participating in the Aggression Replacement Training were observed to have a lower level of anger and a lower level of readiness for physical and verbal aggression. 2. Convicts also showed lower levels of hostility towards other people after training. 3. In addition, a change in functioning during imprisonment was observed among the convicts affected by the impact, which resulted in a decrease in the number of disciplinary penalties applied in the prison.