Foster family placements of children "at risk" often break down prematurely. In this paper the psychosocial characteristics of children in foster and residential care in Holland are analysed to identify some provisional criteria that can increase the success of foster family placements. Successful placement was found to be associated with young age of the child, and with the absence of serious emotional and behavioural difficulties at the time of the placement. Further factors influencing success were: a low involvement of the birth parents, a careful selection of foster parent families, a "good" match between the problems of the foster child and the capacities of the foster family to care and rear, a good preparation of all parties involved during the process of placement, and professional guidance during the whole process of foster care.