Children's right to participate as enshrined in Article 12 of the United Nations Convention on the Rights of the Child is increasingly evident in the rhetoric of policy documents as well as in practice and research with children and young people. Children's participation in research is being facilitated in a range of creative ways, including as researchers and advisory group members. This article presents a case study documenting and describing the process by which children from a special and mainstream primary school participated, via their school councils, in the design and development of research instruments and data collection procedures for a research study concerned with exploring the development of a preventative child abuse education programme for primary school pupils in Northern Ireland. Children were involved in three important tasks: critiquing and considering the format and content validity of the Children's Knowledge of Abuse Questionnaire, devising guidelines for being safe while collecting photographic data with disposable cameras, and devising a procedure for matching child and parent questionnaire data. This process of involving children is described and the outcomes for the research process and the children themselves are explored. (Contains 3 tables and 1 figure.)