This paper aims at examining what are causing differences in altruistic bequest motive between Japanese and American parents. The evidence shows that the Americans are more altruistic than Japanese, and there is a significant difference between these two countries when all the other socio-economic variables controlled. Gender, household income, age and faith in religion have a significant impact on respondents’ bequest motive. The Blinder-Oaxaca decomposition shows that more than 95% of the difference is explained by the differences in coefficients instead of the endowment effect.