Sibling relationships are one of the most important relationships in life of every person. Functions of their bonds are numerous, some of them are socialization of the child, providing a role model during childhood and reducing the effect of trauma on the child. In the context of alternative care sibling relationships become even more important as sources of resistance in overcoming uncertainty and difficulties in which children find themselves. Attachment theory emphasizes the importance of contact development and quality of the close relationships, and family systems theory explains the impact of interpersonal family relationships and other individuals on sibling relationships. Since awarness of the importance of these relationships began to awaken only few years ago there is no much professional and scientific work dedicated to this topic. Therefore, this paper will highlight some specifics of the sibling relationships, especially in alternative care and list significant existing research in this context. In addition, there will be presented the positive outcomes of shared and negative outcomes of separate placement, and the challenges that siblings in alternative care must deal. In conclusion, guidelines for proffesionals working with siblings in alternative care are highlighted, as well as ways in which they can contribute to the development of better relationships between brothers and sisters in alternative care.