OBJECTIVES: Patient-reported outcomes in clinical research are of increasing importance, especially in the study of pain. The objective of this research was to explore whether there were differences in respondents’ self-report (EQ-5D profile and EQ-VAS) and valuation (based on TTO) of pain between populations in Japan and two Western countries (Spain and UK) using the EQ-5D-3L and -5L instruments. METHODS: EQ-5D data from respondents in the UK, Japan, and Spain were analyzed to explore whether they self-reported pain differently on the EQ-5D profile. Each data set was intended to represent the adult population in each country. In total, five data sets were evaluated: two EQ-5D-3L data sets, which included both self-reported health and valuation data from the UK and Japan, and three data sets for EQ-5D-5L, which contained only self-reported data from the UK, Japan, and Spain. We also explored the relationship between respondents’ self-reported EQ-VAS and EQ-5D profiles. Time trade-off results from Japanese respondents and UK respondents were compared using t-tests. RESULTS: Respondents in Japan reported pain less frequently than respondents in the UK on both the EQ-5D-3L and EQ-5D-5L. A slightly larger proportion of Spanish respondents reported “no pain” compared with Japanese respondents on the EQ-5D-5L. The ‘pain/discomfort’ dimension had the largest impact on respondents’ self-reported EQ-VAS among the five dimensions of the EQ-5D-3L in Japan. Japanese respondents were less willing to trade-off time to avoid pain/discomfort than respondents in the UK. CONCLUSIONS: These results provide prima facie evidence of differences in the way Japanese and European respondents self-report and value pain/discomfort. Furthermore, this study may facilitate the comparison and aggregation of EQ-5D data obtained in multi-country studies involving Japan. As no additional clinical or health information was included to contrast results from EQ-5D data, further studies are needed to confirm these findings and to explore their implications.