To describe the clinical features of hereditary breast and ovarian cancer (HBOC) and BRCA pathological variants in Japan, a nationwide registry project was launched by the Japan HBOC Consortium since 2015. From 2019, the main registry project institute was transferred to the Japanese Organization of HBOC (JOHBOC). The registration project has continued till date. Yearly, the registration data, collected until the end of August, are compiled in a dataset. Here, we report the results of the sixth dataset in 2021. In 2021, 48,038 individuals who underwent BRCA genetic testing and blood relatives who developed cancer from 105 medical institutions in Japan were registered. Of these, 12,976 individuals underwent BRCA genetic testing for the first time in their families. Of these, 16.4% developed pathological variants in BRCA1/2, and 3.6% were cases of uncertain pathological significance. Variants of unknown significance (VUS) included inconclusive diagnoses. For insurance coverage in Japan, each diagnostic criterion for conducting BRACAnalysis indicated a positive rate of ≥20%. Overall, 188 and 430 individuals who underwent risk-reducing mastectomy (RRM) and risk-reducing salpingo-oophorectomy (RRSO) were enrolled, respectively. From 2022, the mutation positivity rate could not be calculated because mutation-negative patients were not registered. There is a need to report a wider range of information because cases of prostate or pancreatic cancers, which are recently being covered under medical insurance, also has to be registered. Therefore, cooperation is required among clinical departments to ensure clinical information input. Furthermore, follow-up registration is not being fully documented because of the extensive time and burden required in the yearly documentation. However, the data will be fundamental and important for use in routine clinical practice.