The CLS study (Social Participation in the Life Course of Young Adults) is the first long-term study in Germany on the so-called ‘Leaving Care’ of young adults. Over a period of several years, this study examines the transition of young people between life in a foster family or residential group/other assisted living arrangements and adult life. A large number of different aspects of life are surveyed, so that a detailed picture of the young people’s life situation can ultimately be depicted. For example, questions such as: How do young people in transition live, learn and work? How do they organize their everyday lives? What are their goals and aspirations? To this end, around 1,500 young people aged 16 and over will be interviewed in person (CAPI) or by telephone (CATI). Up to seven survey waves are planned. The client is the German Youth Institute (DJI) in Munich, partners are the Society for Innovative Social Research and Social Planning (GISS), Bremen, the International Society for Educational Support (IGfH), Frankfurt, and the Institute for Social and Organizational Pedagogy at the University of Hildesheim.