We report here on a case of 51-year-old woman with metastatic small cell carcinoma of the breast that came from her cancer of the uterine cervix. She underwent radical hysterectomy with bilateral salpingo-oophorectomy due to small cell carcinoma of the uterine cervix, and adjuvant radiotherapy was administered to the pelvis. Breast metastasis with a palpable mass then occurred 3 months after the primary surgery. Simple mastectomy and adjuvant chemotherapy were performed. She initially showed a good response to the therapy, yet she ultimately died of multiple metastases with a fulminating disease course. This is an extremely rare case, and only 1 similar case has been reported earlier, so we report on this case along with a review of the relevant literature.