We report a case of bilateral breast metastases from Ewing sarcoma of the femur. A 40-year-old woman presented with Ewing sarcoma of the left thigh, treated by complete surgical exeresis and chemotherapy. Secondary, a large tumor appeared in the left breast. Bone scintigraphy, chest, and abdominal computed tomographic scan were normal. A breast biopsy found a malignant tumor composed of small round cells consistent with the initial diagnosis. After the first cycle of chemotherapy, a tumor was discovered in the controlateral breast. After 5 cycles, residual tumors persisted in the 2 breasts. Tumor exeresis was performed and found bilateral breast metastases of Ewing sarcoma. Because of the early recurrence of the left breast tumor, segmentectomy of the right breast and left mastectomy were performed. The histopathological analysis confirmed Ewing sarcoma metastases in the left breast. Despite local radiotherapy, the clinical course was marked by lumbar bone metastasis, local chest evolution, and progression of the disease. Metastases to the breast by extramammary malignant neoplasms are unusual. Sarcoma is an extremely rare cause of breast metastases and our case is the first report of breast metastases from Ewing sarcoma.