Nasopharyngeal carcinoma is the second most common type of malignancy in Southern China. Metastatic sites are usually multifocal and involve the bones, lungs and distant lymph nodes. To date, there have been no studies with regard to nasopharyngeal carcinoma metastasis to the mammary gland. In the current study, the case of a 56-year-old female with nasal obstruction, epitaxis and a bilateral neck mass is presented. Following a series of examinations, the patient was diagnosed with nasopharyngeal carcinoma (cT3N3M0). Subsequently, the patient received radical radiation therapy. After three months, a mass was identified in the left breast, together with enlargement of multiple lymph nodes in the left axilla. The patient underwent a mastectomy and pathological examination revealed that the breast mass and axillary lymph node tissues were derived from the nasopharynx. To the best of our knowledge, this is the first report of a nasopharyngeal carcinoma that metastasized to the mammary gland.