Breast tissue is an unusual site for metastatic disease, particularly for non-small cell lung cancer (NSCLC). Aside from contralateral breast cancer, the most common tumors metastasizing to the breast are malignant melanoma and hematopoietic malignances. We recently experienced a case of a 49-year-old female patient with solitary metastasis of NSCLC to ipsilateral breast tissue. She was diagnosed as NSCLC of left lung and underwent left upper lobectomy in 2001. She was then treated with etoposide/cisplatin chemotherapy and radiation therapy. After 35 months, she was referred to our breast clinic because of a nodular opacity in the left breast revealed by screening breast ultrasound, which proved to be of pulmonary origin. She was treated by wide excision and with docetaxel/cisplatin chemotherapy. However, 37 months after breast surgery, a metastatic lesion developed in the same breast and she received modified radical mastectomy. We report this case with a review of the literature.