Almost all breast cancer patients are treated with chemotherapy, hormone therapy, molecular targeted therapy, radiotherapy, and surgery alone or in combination. It is reasonable and standard to choose a combination according to clinical practice guidelines. One of the objectives of clinical practice guidelines is to standardize medical care and provide equal quality of care for patients wherever they live in Japan. Recently, many clinical trials have been conducted internationally. Therefore, it is necessary to standardize medical care from an international viewpoint. In this paper, the breast cancer clinical practice guideline developed by the Japanese Breast Cancer Society was compared with other guidelines which have been already developed and are frequently utilized all over the world as well as in Japan.