Social exclusion is a popular and widely used concept in the social sciences as well as in current European policy rhetoric. However, there is no general agreement on the content and use of the term; it has been used differently and for different purposes in different historical and social contexts. In this article, the social exclusion is understood as life-historical phenomenon. Two cases have been selected as representing the most extreme trajectories based on a larger follow-up study concerning former students of residential institutions for young people with emotional and/or behavioural difficulties in Finland. The cases give us an example of a detailed life-course analysis, with the emphasis on risk and protective factors and demonstrate that the process of social exclusion is a complicated issue that cannot totally be understood by analysing the statistical connections between certain risk factors and the life-course.