Temperament styles of 4,628 South Korean children, ages 9-17, are described in reference to possible gender and age differences and compared with those of 3,200 US age peers in the light of Jung's theory of temperament as modified by Myers and Briggs, one that highlights four bipolar qualities: extroversion-introversion, practical-imaginative, thinking-feeling and organized-flexible styles. It was found that South Korean children strongly prefer extroverted to introverted, imaginative to practical, feeling to thinking and flexible to organized styles. In contrast to South Korean males, South Korean females are more likely to prefer extroverted, feeling and organized styles. Age differences are seen on all four styles, with children generally expressing a greater preference for introverted, practical, feeling and flexible styles with age. In contrast to US children, South Korean children are more likely to express preferences for extroverted, imaginative, feeling and flexible styles. These preferences also are more frequent in South Korean than US males and females as well as all four age groups. Findings and implications of this study are discussed. (Contains 1 note and 3 tables.)