Jim Walker explores the relevance of attachment theory to fostering and adoption. He begins by focusing on three important qualities for substitute carers: the ability to manage a wide range of feelings, both in oneself and in others; the resolution of past losses and traumas; and the acquisition of reflective function. Emphasis is then paid to gaining an understanding of the attachment patterns of both children and potential substitute carers. Current ideas from attachment theory can help to inform both the selection of substitute carers and the needs and vulnerabilities of looked after children. Ways of matching the child with the carers are discussed, including an analysis of particular areas of vulnerability. Further discussion highlights some of the dilemmas which these ideas might create for current social work practice.