This paper's starting point is the dynamic changes and shifts in the field of measuring and monitoring children's well being. In the paper we focus on one specific change--the "new" role of children in measuring and monitoring their own well being--a role of active participants rather than of subjects for research. We then turn to present based on a sequence of arguments and findings what role children should carry in measuring and monitoring their well being. Followed by a presentation of five possible roles for children's involvement in such studies and in regard to the specific roles existing knowledge from various studies and suggested directions for future research are presented. The danger of children's involvement in such studies are then discussed, followed by a presentation of what children think on this issue. Finally, we conclude that the potential involved in children's involvement is much greater than the hazards.