Breast cancer patients who achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) usually have a favourable prognosis. We report on a patient with early metastases to the brain after achieving pCR. The primary tumour was 7.0 cm in diameter with axillary lymph node metastases, hormone receptor-negative, human epidermal growth factor receptor-2-positive (3+), and histological grade 2 with 60% of cells positive for Ki-67. The patient underwent NAC followed by surgery, and achieved pCR. Five months after surgery, during adjuvant treatment with trastuzumab, she developed headache and dizziness. Brain imaging revealed multiple metastatic brain tumours. She received whole-brain radiotherapy followed by lapatinib and capecitabine therapy. At 7 months after surgery, she remains alive with a persistent mild headache. Physicians should be aware of the possibility of early brain metastases, and consider new treatment strategies to prevent brain metastases in high-risk patients who achieve pCR.