The purpose of this study was to find out about the presence of unannounced home visits in foster families based on a survey of Swedish municipalities. The study also aimed at increasing knowledge about why unannounced home visits were made. In order to achieve the purpose of this study, mixed methods were used in both a quantitative and qualitative approach. The quantitative part of the study consisted of a census where all Swedish municipalities' guidelines and procedures for the prevention of foster homes were collected. Qualitative interviews were held with five social services, which stated in their guidelines that unannounced home visits should be made. To analyze both the study's quantitative and qualitative results, theories of legitimacy and power were used. The study concluded that the law on follow-up of foster homes gives municipalities a large margin of interpretation because the visits are regulated by the municipalities themselves. Another conclusion from the study was that no one knows which follow-up methods that really helps. Therefore, evaluations and research on follow-up of foster care must be established.