The article shows the importance of post-penitentiary assistance for general prevention (level of public security) and for individual prevention (ways of readaptation of a person leaving a penitentiary). The paper consists of several parts. The specificity of supporting the former prisoners in the countries of Western Europe was described in the first one. The characteristics of post-penitentiary assistance in Poland was presented in the second part. This issue has been described in two aspects – the historical one and in the context of applicable executive criminal law. The third part of the article contains an analysis of two arguments that justify to provide the post-penitentiary assistance – experience of readaptation difficulties by the former prisoners and preference for the criminal lifestyle by people leaving the penitentiaries. The last part of the study contains postulates regarding changes in the provision of postpenitentiary assistance in Poland.