The study aims to examine the influence of staying in immigration detention on the decision-making process of irregular migrants in immigration detention regarding leaving the country. It will do so by making an inventory of the factors and roles of immigration detention in these decision-making processes. Such an inventory makes it possible to map the influence of staying in immigration detention on the decision-making process of irregular migrants regarding return. Moreover, the study will determine to what extent migrants in immigration detention consider immigration detention a specific deterrence to return to the country of origin.