objective: the purpose of this study was to examine the reliability and the convergent validity of the children anxiety sensitivity index (casi) with dsm-iv anxiety disorder symptoms, by comparison with the screen for child anxiety related emotional disorders (scared), in a community sample of brazilian children and adolescents. methods: children and adolescents from five schools were selected from a larger study that aimed to assess different aspects of childhood anxiety disorders. all participants completed the casi and the scared. results: this study supported the reliability of the casi total score. girls reported higher total anxiety sensitivity scores than boys and there were no differences in total anxiety sensitivity scores between children and adolescents. this study showed moderate to high correlations between the casi scores with scared scores, all correlations coefficients being positive and significant. conclusions: our findings demonstrate an appropriate reliability and evidence of convergent validity in the casi in a sample of brazilian children and adolescents.