Objectives: The purpose of this study is to evaluate the reliability and validity of the Junior Temperament and Character Inventory(JTCI), which is a child and adolescent version of Temperament and Character Inventory. Method: JTCI was translated to Korean and applied to 796 children(male=402, female=394, age=11.0±0.9), and their parents. Internal consistency was calculated by Cronbach`s α. A test-retest study was done after 3 months with 115 subjects. Factor analysis for the temperament and character factors were performed using principal component analysis, rotating factor varimax. Results: Cronbach`s α values of the JTCI scales ranged from .52 to .77 for the temperament scales except persistence(.09), and from .47 to .65 for the character scales. Test-retest correlation was relatively low. Factor analysis of temperament showed 3 factors out of 4 temperament scales, but couldn`t extract clear differentiations in character dimension. Intercorrelation between 7 factors were clear each other significantly. Female showed higher reward dependence, persistence, self-directedenss and cooperativeness than male. Discussion: Although reliability is relatively low, this study suggests JTCI is a useful tool to evaluate biosocial model of personality in children population. Character dimension should be assessed with the careful consideration of their development.