Secretory carcinoma is one of the least common forms of breast cancer and demonstrates distinctive clinical and pathological characteristics. We herein report a case of secretory carcinoma of the breast in 3 year and 1 month-old girl. At presentation, the patient had a 2.5cm sized mass on her left breast which was firmly attached to the overlying nipple. The aspiration cytologic findings of the tumor were consistent with a secretory carcinoma. After confirming malignancy by frozen section diagnosis, a modified radical mastectomy was performed and secretory carcinoma was finally diagnosed. To our knowledge, secretory breast carcinoma in children has not been reported previously in Korea and this seems to be the youngest case of secretory carcinoma of the breast which had been reported in English literature.