We report an elderly patient with locally advanced breast cancer who received long-term fulvestrant therapy.The patient was a 75-year-old woman who presented with a right breast lump.She noticed the tumor 4 years and 6 months ago, but she had not visited any hospital.However, her daughter brought her to our hospital.The tumor was 73mm in diameter.A core needle biopsy for breast tumor led to a diagnosis of an invasive ductal carcinoma, positive for estrogen receptor(ER)and progesterone receptor(PgR), and negative for HER2/neu.The Ki-67 positive cell index was 20%.We performed a whole- body checkup, and confirmed the diagnosis as T4cN1M0, Stage III B.She initiated endocrine therapy by letrozole(2.5 mg/ day).After 1 year and 6months, tumor marker levels increased.We changed the endocrine therapy to fulvestrant(500mg/ month).For the next 2 years and 6 months, this therapy was effective.Her axillary lymph node metastases disappeared and tumor size decreased(60%).She underwent muscle-preserving mastectomy plus axillary lymph node dissection.The pathological diagnosis from the resected surgical specimen was confirmed as invasive ductal carcinoma, positive for ER and PgR, and negative for HER2/neu protein expression.The surgical margins were negative, and there was no metastasis in the lymph nodes.She was administered adjuvant endocrine therapy.Four years after surgery, she was well without metastasis.