Carcinosarcoma (CS) of the breast is a rare entity (less than 0.2% of breast malignancies), characterized by the presence of a biphasic pattern of malignant epithelial and mesenchymal elements, and with a high risk of loco-regional recurrence. The diagnosis of CS of the breast is difficult and needs detailed histological investigations to differentiate it from other malignant breast tumors. Expertise and evidence-based information on optimal treatment is very limited due to the low incidence and inconsistent classification. The principles of treatment modalities seem to be similar to others breast malignancies. CS has a different biologic behavior from others breast cancers, being very aggressive in keeping with its high-grade mesenchymal stroma. Still many questions remain about its origin and optimal treatment modalities for better outcome. We report the case of CS of the breast without local or regional recurrence after six years of follow-up in an 82-year-old woman.