OBJECTIVES: Japanese researchers have insufficient health utility data on the Japanese population. Thus, they often resort to using parameters based on UK data in economic evaluations. Therefore, a need exists for an international comparison of EQ-5D tariffs between the UK and Japan as a fundamental validation analysis. The aim of our research is the evaluation of the differences in elicited EQ-5D-3L and -5L tariff scores across the range of different health states derived from the UK and Japanese populations. METHODS: Utility values are acquired from published database. (https://www.ohe.org/publications/valuing-health-related-quality-life-eq-5d-5l-value-set-england and http://www.niph.go.jp/ journal/data/64-1/supplement.xls)Tariffs derived from the two countries are compared using mean and standard deviation　as well as the correlations between countries. RESULTS: The Japanese EQ-5D-3L score was 0.423±0.217, and that for the UK was 0.147±0.312. In the case of EQ-5D-5L, the Japanese score was 0.449±0.154, and that for the UK was 0.391±0.228. The corresponding correlations between countries were 0.74 and 0.91. CONCLUSIONS: We identified that the Japanese and UK EQ-5D-5L tariff are more highly correlated than are the EQ-5D-3L tariffs. One reason for the EQ-5D-3L tariffs being different is that the N3 score, which is a constant that is added if any level-three value is scored, varies substantially between the countries; specifically, the UK N3 score was 19.2 times higher than that of Japan. Although the role of EQ-5D-5L differs from that of EQ-5D-3L, utility data from EQ-5D-5L can be better extrapolated than can EQ-5D-3L utility values.