This study aimed to understand the routine of the adolescent-being, who is under semi-liberty socio-educational measures. A phenomenological research was developed in unit of the Socio-Educational Treatment Foundation (Fundação de Atendimento Socioeducativo), in the state of Rio Grande do Sul, Brazil. Interviews were held with nine adolescents, from February to May, 2009. The Heideggerian analysis un-veiled that this socio-educational measure means a prison for them, something bad. They know they are not in the prison system due to their age and re-cognize they have thrown away their adolescence. In the institution, these youngsters go to school to learn something, to get some job. They express themselves through gossip, ambiguity and occupation. The conclusion is that the teenager is-thrown in that which is determined and remain in impersonality. For social reintegration they need the help of the socio-educational system, mediated by interdisciplinary work, and a support network for which the family, community and State are co-responsible.