Mental health service (MHS) providers confront questions of informed consent for evaluation and treatment of children in state custody who are placed in residential or foster care programs, where legal responsibility is shared between state and parent. There are ethical issues encountered by MHS providers who work with this growing population of children in placement. Matters of informed consent and access to information about treatment influence relationships with the parents, legal guardians, Child Protective Service workers, and the child. These specific concerns are addressed: informed consent, the right to be informed, and the rights of parents or foster carers to participate in a child's treatment. Recommendations for resolving dilemmas faced by MHS providers are discussed.