The following study investigates the psychological effects of fostering on birth children of foster families. The study was conducted in two parts. The first part involved conducting a series of focus groups to elicit information from birth children on their views and experiences of fostering. This information was then used to design the questionnaire measures for the second part of the study. The second part of the study was carried out via postal questionnaire. Birth children completed questionnaires asking about their positive and stressful fostering experiences and the strategies they use to cope with these experiences. In addition, the General Health Questionnaire was used to measure the children's levels of psychological distress. The parentso f the birth children were also askedt o complete the sameq uestionnairesb asedo n how they felt their child would respond.T heir responsesw ere then comparedt o their children's to investigatep arental awarenessa nd sensitivity to their children's views and experiencesT. wo hundred and fifty-seven questionnairesw ere distributed and forty were returned giving a response rate of 15.6%. The results of the study found that the majority of the birth children rated fostering positively and reported more positive than stressful experiences. Also, most of the birth children adapted well to their fostering experiences and showed few symptoms of psychological distress, however, a quarter were found to reach clinical `casesness' on the GHQ. This latter group of children tended to be males who had encountered more stressful fostering experiences, who tended to view their overall fostering experiences more negatively, and who had a parent who was less sensitive towards their views and experiences. The psychological concept of `resiliency' was drawn upon in the interpretation of these findings.