OBJECTIVES: Screening for breast cancer can result in earlier diagnosis and better health outcomes, but is less aggressive in Japan than in some other countries, such as the United States (US).  This study was conducted to assess how outcomes differ among breast cancer survivors according to the presence of symptoms at diagnosis, and to compare stage of diagnosis across Japan and the United States (US). METHODS: Data came from the combined 2010-2014 Japan National Health and Wellness Survey (NHWS) and 2015 US NHWS.  The NHWS is an Internet-based self-reported survey administered to the adult population of the respective country. Those reporting physician diagnosis of breast cancer were asked which stage their breast cancer was diagnosed, how it was detected, and whether they experienced symptoms prior to diagnosis.  Health status during at the time of the survey was assessed using either SF-12v2 or SF-36v2 health survey. RESULTS: A total of 1,053 respondents in Japan had ever been diagnosed with breast cancer, of which 178 (16.9%) had experienced symptoms before being diagnosed.  These respondents had lower mental component summary (45.0 vs. 48.6), physical component summary (48.1 vs. 49.4) and SF-6D health utility (0.70 vs. 0.74) (all p<0.05) than those who had not experienced symptoms by the time of diagnosis. Stage of diagnosis differed across countries (overall p<0.001), with the greatest difference being the percentage diagnosed at stage 0 (14.4% in Japan vs. 24.8% in US). Diagnosis by mammogram was also less common in Japan than in the US (17.9 vs. 49.9%, p<0.05). CONCLUSIONS: Experience of symptoms at the time of breast cancer diagnosis is associated with worse health-related quality of life among survivors in Japan.  Combined with the later stage of diagnosis, these results suggest women in Japan could benefit from increased screening for breast cancer.