The prison aftercare is an important aspect in preventing criminality since it comprises activities whose goal is to prepare and strengthen the inmates to enable their successful reintegration into community and life in freedom in accordance with the rule of law. Activities to prepare inmates to leave a prison and return to community start while they are still in prison and continue upon their release. Even though inmates work on changing their behavior and undergo a preparation for a smooth resocialization during their sentence, their reintegration into community still represents a major challenge for them. Successful reintegration into community and decreasing the risk of repeating the criminal offense are not only in the best interest of the offenders but also of the community to which they return after the imprisonment. Drug addicts represent a group of prisoners which is one of the most numerous and the most difficult to treat. Following their imprisonment, they often face double stigma since they have both problems with addiction and criminal offences. For this reason, it is important to ensure that they have as comprehensive prison aftercare as possible to enable their life in freedom in accordance with law and social norms, which is the aim of a prison sentence. This thesis is trying to provide an overview of national and international literature outlining certain characteristics of criminal offenders and interrelation of addiction and criminal behavior. Additionally, the thesis describes collaboration of different systems of a prison aftercare and gives an overview of the best practices in the world and in Croatia. Drug addicts who are also criminal offenders are a highly stigmatized group, rejected from their communities and often from their families, so when talking about prison aftercare it is of special importance to discuss options for their successful reintegration in the society and decreasing the risk of repeating criminal offences.