The purpose of this study was to compare the degree of happiness between Korean mothers and Japanese mothers who have 3- to 5-year-old children going to kindergarten. The subjects of this study were 168 Korean and 163 Japanese mothers. They were randomly chosen. We measured and analyzed 331 mothers' happiness by Ryff's psychological well-being items. The results of this study reveal that Korean and Japanese mothers had significant difference in 5 factors of mothers' happiness; positive relationships, self-acceptance, environment mastery, purpose of life, and personal growth were significant difference between Korean and Japanese mothers. In addition, there was significant difference between Korean and Japanese mothers when we analyzed the subjects in different groups according to age of mothers, number of child and age of child.