Fibroadenoma of the breast is a common benign disease, occurring mainly in females younger than 30 years of age. Infant fibroadenoma is extremely rare. Here, we report on a 16-month-old female with a 6 month history of unilateral progressive breast enlargement. Upon clinical evaluation, a palpable mass was observed in the upper and outer quarter of the right breast. The single tumor was solid and well circumscribed. Various clinical examinations were performed, including determination of hormone levels, ultrasound, mammography, magnetic resonance imaging, as well as the collection of a fine needle aspiration. The results showed that the sex hormones were present at normal levels. The size of the tumor was approximately 3 × 3 × 3 cm. Enlarged lymph nodes were not detected in the axillary region or any other regions. The tumor was removed surgically and fibroadenoma was diagnosed post-operatively. The patient was followed up for 38 months and no tumor recurrence was observed.