The investigation, Quality of life in prisons and intervention programmes, looks at whether the treatment programmes carried out in the prisons influence the perception of quality of life in the penal context. A good social atmosphere in the prisons is related to less conflict, a lower suicide rate, a greater legitimacy of the system, greater security inside the prison and less radicalization of the prisoners. By making a survey among the inmates the researchers have tried to find out their degree of participation in the treatment programmes, their opinion of them and their assessment of their quality of life inside the prison. The results have been substantially different according to the prisons that have cooperated on the study, in terms of both participation and motivation for following them and their consequences.