This study investigated the sibling relationships in adolescents discharged from child care institutions. The purpose of this study was to influence the development of social welfare intervention plans to support sibling relationships in brothers and/or sisters who grow up in child care institution. We enrolled four adolescents who had grown up together with their sibling(s) at the same child care institution. We examined the individual responses of the adolescents after in-depth interviews, which were conducted between March and August 2017. Our qualitative case study revealed that the adolescents had not been exposed to sufficient interactions or opportunities at the child care institutions that enabled them to form strong sibling relationships with each their sibling(s). After being discharged, adolescents remained on awkward terms with their sibling(s) onto adolescence, but did not sever family ties. Based on these findings, the social welfare interventions suggested in this study aim to promote and support positive sibling relationships among siblings discharged from the same child care institutions.