Introduction: Pleomorphic adenoma is the most common type of salivary gland tumors. That may rarely be found elsewhere such as skin, palate, maxillary sinus, nasal septum, larynx, tracheobronchus, lung, lacrimal gland, and breast.Materials & Methods: We present, herein, the case of a 47-year-old woman found to have a pleomorphic adenoma, or the so-called mixed tumor, of the breast. The patient presented a hard mass, 3cm in diameter, located just beneath the left areola. Physical examinations suggested a diagnosis of breast carcinoma.Findings: The results of both ultrasonography and mammography indicated a benign neoplasm. Microscopic examinations of an excisional biopsy specimen finally confirmed the diagnosis of pleomorphic adenoma.Discussion & Conclusion: As it is a rare benign tumor, pleomorphic adenoma of the breast has been mistaken for a malignant tumor clinically, mammographically, cytologically, and even by frozen section. Thus, an awareness of this disease in the breast will help to prevent misdiagnosis and overaggressive surgery.