The appearance of pulmonary metastasis more than 15 years after primary treatment for breast cancer is rare. We herein report the case of a breast cancer patient with solitary pulmonary metastasis, after an 18-year disease-free period, treated with resection. A 66-year-old Japanese woman was found to exhibit an abnormal shadow on a chest X-ray. She had undergone a left mastectomy for breast cancer 18 years previously. The nodule was suspected to be either metastatic or primary lung cancer, and thus thoracoscopic surgery was performed. The histologic diagnosis was metastasis from breast cancer. Pulmonary resection in breast cancer recurrence is an important diagnostic tool that allows for a differential diagnosis with primary lung cancer. The clinical implication of surgery for a solitary pulmonary metastasis from breast cancer is discussed in this report.