A few comprehensive reviews of the effectiveness of prevention programs of mental disorders in school-age children ((Greenberg et al., 2003) and (Weisz et al., 2005)) conclude that while several well-designed studies demonstrate the potential of preventive intervention, greater attention and ongoing rigorous research is critical. The benefits and difficulties of mounting prevention programming specifically targeting child anxiety, the most common of mental disorders, and the concomitant challenges for clinicians are presented here. Two examples of school-based prevention are described: one of a large-scale, primary prevention program specifically targeting child anxiety in public school children in a large Canadian province, and a specific case of an individual child that came to the attention of clinicians during the universal implementation. (Contains 1 table.)