Schwannomas arise from the neural crest-derived Schwann cells. Their most common locations are the extremities, neck, mediastinum, retroperitoneum, and cerebellopontine angle. They have rarely been reported to occur in the breast. We herein report on a case of schwannoma of the breast in a 30-year-old woman. The ultrasonographic examination showed a well defined ovoid hypoechoic mass in the upper outer quadrant of her left breast. A presumptive diagnosis of fibroadenoma was made, and the mass was then removed. The histopathologic and immunohistochemical features confirmed the diagnosis of schwannoma of the breast.