Objectives This study aim to explore the relationship between mindfulness and anxiety and the mediating effects of emotion regulation and worry on the relationship between mindfulness and anxiety. Methods The data were analyzed from 289 elementary school children in Seoul. Reliability analysis, technical sta-tistics, correlation analysis, and mediating effect analysis of each scale were conducted using the SPSS 18.0 and PROCESS Macro Model 4.2. Results Research results were as follows. First, the correlation between mindfulness and anxiety were significant, and regression analysis showed that mindfulness significantly predicted anxiety. Second, the mediating effect of emotion regulation and worry were significant in the relationship between mindfulness and anxiety. Conclusions This study was verified that children's mindfulness is a useful variable that directly affects anxiety re-duction and indirectly through emotional control and worry. It also provides useful information for making mindful-ness-based interventions. Considering the results that the indirect effect through worry was greater than the di-rect effect of mindfulness on anxiety, it suggests the need to include mindfulness activities on children's worry.