The aim of this guidance paper, produced by a working group on behalf of the Department of Children and Youth Affairs (DCYA), is to advise on good practice principles for undertaking research with children (defined in Ireland as people below the age of 18). The need to protect children when they are involved in research is self-evident, but it has taken a relatively long time to translate this notion into policy and practice. The history of research endeavour includes many unethical practices involving children from intrusive and invasive procedures, to the over-investigation of some populations. Organisations caring for children sometimes regarded them as a ready source of research data with little regard to the ethical issue...