The purpose of this study was to investigate adherence to adjuvant endocrine therapy (ET) and the factors affecting demotivation and motivation to continue adjuvant ET. In patients with hormone receptor-positive breast cancer in Japan, an online survey was conducted from June to July 2021 to investigate the treatment effects, side effects, concerns about side effects(for demotivation only), convenience of hospital visits, treatment duration, concerns about recurrence/progression, treatment cost, support from healthcare professionals, and support from family, the patient association, and peers(for motivation only). According to the responses from 263 patients, the most common factor affecting demotivation to continue adjuvant ET was the burden of side effects, and the most common factor affecting motivation to continue adjuvant ET was concerns about recurrence/progression. Continuous relief of the burden of side effects from the early stage of treatment, and mental support for concerns about recurrence/progression, as well as explaining and promoting the risks and benefits of continuing treatment, are considered to lead to motivation to continue adjuvant ET(Fig. 1: Summary of this survey).