Purpose: In an attempt to investigate the differences in the level of stress & mental health between extracurricular learning group and non-extracurricular learning group and level of stress and mental health by the extracurricular learning-related characteristics, this study was carried out in upper grade elementary students. Method: The subjects were 241 students living in 4 small towns in 4th, 5th and 6th grade elementary students. The data were collected by using the questionnaires, and analyzed by SPSS/WIN 12.0 program. Results: First, 64.7% of subjects were receiving extra-curricular learning, and extracurricular learning contents were the main curriculum and foreign language classes in many cases. Second, there were no differences in the level of stress and mental health between extracurricular learning group and non-extracurricular learning group, but also in the area of stress as physical, mental, emotional and behavioral stress. Third, extra-curricular learning satisfaction and learning effects are the major factor affecting mental and emotional stress and mental health. In other words, the group with high satisfaction and effectiveness by extra-curricular learning was less mentally and emotionally stressed and better for mental health than low group. Also, days per week for extracurricular learning affected physical stress and intention to continue extracurricular learning affected mental stress. Fourth, factors affecting whether the intention to continue extracurricular learning were the sex, decision-makers about whether they receive extracurricular learning, extracurricular learning satisfaction and duration of extracurricular learning. Conclusion: From the above results, The fact that the upper grade elementary school students receiving the extracurricular learning did not affect on the stress and mental health. In case of extracurricular group, the effectiveness and satisfaction about extra-curricular learning were major factors affecting mental and emotional stress as well as mental health.