The use of animals in social work is currently booming and experiencing an increasing popularity. By now, animal assisted interventions even find their way into penal institutions and make an important contribution to resocializing prisoners. The aim of this master thesis is to give an insight into the use of animals in Austrian penal institutions, to evaluate the influence on the prisoners and to demonstrate possibilities and limits. The master thesis divides into two parts. Firstly, the theoretical basis of human-animal relationships is discussed. This part evaluates the historic and cultural phases, explanatory approaches and theoretical models. Furthermore, it provides a detailed knowledge about different behavioural aspects of the human- animal relationship and describes the impact on human beings. After that, the focus shifts towards to animal assisted interventions in the field of social work. On one hand, its historic development is shown, followed by definitions and the currently existing approaches of intervention. On the other hand, I present the most important characteristics and fields of applications of animal assisted interventions as well as the preconditions for the professionals and their work related methodological bases. Afterwards, the scope upon the detailed use of animals in penal institutions is enlarged and the current research agenda is explained. The second part discusses the empirical findings of the guided interviews with experts and seeks to answer the essential research questions, which are: “What are the possibilities and limits of the use of animals in the Austrian penal system?” and “Which kind of influence do animals have on the resocialization of criminal people?” The collected data show that animals have a variety of positive impacts on prisoners and due to this fact they are able to make a large contribution to their resocialization.